Mid-Season Fertilizing: How to Know What Your Vegetables Actually Need - Ep. 306

[00:00:00] So we are officially into summer and this is the time when you might start noticing some things happening in the garden. Maybe you pull back a tomato leaf and you spot the pale green creeping up from the bottom. Or your corn looked great two weeks ago and now it's just sort of stalled. Or you've got a zucchini putting out flower after flower but no fruit is setting and you're wondering if you should go dump some fertilizer on it.

[00:00:30] What I am seeing right now in gardening groups online is people showing pictures of their plants and describing the symptoms and nine times out of ten people are coming back and saying it needs to be fertilized. It needs potassium, it needs phosphorus, it needs nitrogen. Right? But what I just described are three different situations and they need three different responses and for one of them more fertilizer right now is actually the wrong call entirely.

[00:01:01] Welcome back to Just Grow Something. I'm Karin Velez, specialty crop farmer, horticulturist and garden educator. This podcast is where we take the questions that gardeners are actually searching for or asking in their online groups and give them the research backed answers that they deserve. Today we are talking mid-season fertilizing because right now in June your vegetable garden is hitting its productive stride or at least it should be. And the fertilizing decisions that you're going to be.

[00:01:30] And the fertilizing decisions that you make in the next few weeks will either carry your harvest forward or work against it. So today we'll cover why nitrogen timing matters more than nitrogen amount. The difference between how your fruiting crops and your leafy crops need to be fed. How to read your plants for actual deficiency signs. How to side dress correctly. And when to hold off on fertilizing entirely. Let's dig in.

[00:02:02] Before we get into it, quick shout out to everyone who responded to my little pity party of sorts in last week's email newsletter. If you are not on the weekly newsletter, head to justgrowsomething.com and scroll to the bottom of the page to sign up. I usually send out one email per week with some juicy tidbits of information that either weren't covered on the podcast or that follow up to one of the episodes.

[00:02:28] But I got caught up in the craziness that is late spring around here, plus recording another podcast and running two other businesses, plus training for a 100 mile race in October. And I basically failed to send out a newsletter for, I think, four weeks, which is unheard of for me and hasn't happened probably in the last three years.

[00:02:51] Anyway, in begging my gardening friends on the newsletter list for forgiveness in last week's email, some of you sent me some very, very sweet responses. And I thank you all tremendously. I am trying to answer everyone, but there were a lot of you. And I was a little overwhelmed at the response. So if you don't get a response from me, please know that I did read your email. I read every single one of them.

[00:03:20] They're still coming in. And I am ever so grateful for your kindness. I am also very grateful for the topic and the episode suggestions that you have been sending me. So if you're not on the email list, hit the link in the show notes. And if you have a topic or an episode idea, please feel free to send me an email as well. I love episode suggestions. Okay, so why is midseason fertilizing its own conversation?

[00:03:50] Most gardeners start the season by working in either some compost or a balanced fertilizer or both into the soil before planting. And if you did that, good. That was the right move. But here's the thing. That pre-plant application oftentimes is not meant to carry your garden all the way through the harvest.

[00:04:14] Nitrogen, which is the nutrient that is most critical to active plant growth, is also the one that's most likely to run out midseason. And this is for two reasons. The first one is that nitrogen leaches. So unlike phosphorus and potassium, which bind to soil particles and stay put, nitrate nitrogen is water soluble. It moves with water, which means it also moves down through the soil profile and out of reach of our plant roots.

[00:04:44] Heavy spring rains, irrigation, even just normal precipitation across the growing season carries nitrogen out of your root zone. It also leaches from soils during the winter, which is leaving us very little at the start of each growing season. And then that same process continues through like the heavy spring rains and then summer with heavy watering from us. The second thing is that your plants are consuming it.

[00:05:10] So as vegetable plants move from establishment into rapid vegetative growth and then into flowering and fruiting, their nitrogen demand rises pretty sharply in some different spikes. The pre-plant supply usually gets pretty drawn down. And so when demand outpaces what's in the soil, you start to see it in your plant.

[00:05:32] Nitrogen, phosphorus, and potassium are all open to becoming deficient and they possibly are going to need some supplementing throughout the growing season. But of all of these three, nitrogen is the one that runs out the fastest and the most predictably, which is why mid-season side dressing is almost always a nitrogen conversation. Potassium and phosphorus just don't leach out of the soil the way that nitrogen does.

[00:06:01] So they typically should be added at the start of the season. And then generally that's all you need. The only exception to this is when you're growing in small containers. That small amount of soil can only hold so much in nutrients. So I always recommend feeding a balanced fertilizer throughout the season in containers. But for the rest of us, nitrogen usually ends up being the big story in the mid-season. Now this is where most of that fertilizing advice goes off track.

[00:06:30] The question isn't just, does my garden need more nitrogen? The question is, which crops need it and when and in what form? Because pushing nitrogen at the wrong moment in a plant's development, especially for fruiting crops, can actively reduce your yield.

[00:06:49] So what happens is you put a big nitrogen hit on tomatoes before fruit set and you get beautiful, lush, dark green plants with almost no fruit. The nitrogen drives vegetative growth. The plant keeps putting energy into stems and leaves instead of the flowers and the fruit. So you just basically fed your way into a problem and into a crop shortage. So let's talk about how to get this right.

[00:07:19] Starting with that kind of fundamental split between fruiting crops versus our leafy crops. If you're growing crops where the leaf is what you harvest, so lettuce, spinach, kale, chard, collards, arugula, even basil, nitrogen is your friend all season long.

[00:07:47] I usually say not to really feed herbs, but in the case of basil, that's probably the only one that I take an exception with. All of these crops convert nitrogen directly into the part of the plant that we're eating, right? So higher nitrogen equals more leaf, better color, better texture, faster succession harvests.

[00:08:09] So leafy vegetables are naturally higher nitrogen feeders relative to fruiting or even our root crops. So in practical terms, your leafy crops can benefit from a nitrogen side dressing fairly early in the season, usually within two or four weeks of transplanting or when your direct seeded crops are about two to three inches tall.

[00:08:33] And they can handle repeat applications across the season, especially if you're doing like cut and come again harvesting. So for our quick turnover greens like lettuce that we're successively planting, right? A liquid plant food every couple of weeks or three weeks is pretty reasonable. For heavier crops like kale or chard that you're harvesting across months, then a side dressing every like four to six weeks is going to keep that growth active.

[00:09:02] The caveat here is that even leafy crops can be over fertilized and that can cause excessive leafy growth alongside all kinds of other stress responses, which is going to increase their vulnerability to pest and disease problems. So the goal is steady, consistent feeding, not maximal applications.

[00:09:24] And then when we look at our coal crops like broccoli and cabbage and cauliflower, these fall into a slightly different category. They're leafy in structure, yes, but we're harvesting ahead, right? Which requires the plant to build real mess. So generally speaking, we're side dressing like cabbage about 30 days after we transplanted. And that timing applies pretty similarly to broccoli and cauliflower.

[00:09:53] These crops are heavy feeders, but they're sensitive to very high nitrogen late in development, which can push excessive leaf growth at the expense of that head formation. So you want to get that side dressing in during the vegetative growth phase, not after the head is starting to form. So for mid-season, we're skipping our coal crops and just letting them finish without the extra nitrogen.

[00:10:21] Save that for maybe your fall crops of those. Now, for fruiting crops, the nitrogen timing is everything. This is where mid-season fertilizing gets a little complicated and where we can see the most mistakes. So when I say fruiting crops, I'm topping things like tomatoes, peppers, cucumbers, squash, eggplant, melon, right?

[00:10:47] They all need nitrogen to grow, but they need it timed to their developmental stage. And that is a very meaningful distinction. For tomatoes and other vegetables that are grown for their fruit, mid-season nitrogen should not be given close to the start of fruit set.

[00:11:06] Nitrogen at that stage just diverts that plant's energy towards putting out more of that green leafy growth, and that is going to come at the expense of that flower and fruit development. So we should apply the first nitrogen side dressing when the first fruits are already formed and they are about one-third of their mature size. Okay, so not when the flowers are forming.

[00:11:33] We're not generally doing this at transplant, but when actual fruit is sizing up. That is when the plant's demand for nitrogen starts to rise again. So again, we're feeding before we transplant and then when the fruit is set and it's getting bigger.

[00:11:51] Tomatoes are moderate to heavy feeders overall, but too much nitrogen before and during that early fruit set is going to, again, lead to that really excessive shoot growth. And it also increases blossom and rot. So if you think about it, the plant is pushing all of this leafy growth, and that makes it difficult to push the calcium where it needs to be, which is in the fruit.

[00:12:17] So if you need to apply nitrogen, do it really lightly once the fruit is setting. The same goes for potatoes, by the way. Too much nitrogen is going to produce a lot of vines, but you're not going to have very much in terms of tuber formation. So what should you actually do with your tomatoes right now in June? Look at the plant. If you transplanted in May, which is most of us here in the Midwest, your tomatoes should be actively flowering right now.

[00:12:47] You might have your first small green fruits forming. That is not the time to push nitrogen, so hold off. If you're further south than me and you planted earlier than that, then those first fruits are likely sizing up to about the size of a golf ball right now. That is your signal to side dress and to do it lightly. We got ours in fairly early, and so I actually have tomatoes that I am getting ready to harvest right now.

[00:13:15] So that is the second time that you would actually apply nitrogen, would be after you have harvested your first fruits. So it's on my calendar to go ahead and do a little side dressing. Peppers also follow similar logic. So you want to supply plenty of nitrogen early on. We want to promote that vigorous growth before the fruit sets, and that is going to support the vegetative structure that you need to carry like a heavy fruit load. After the fruit sets, pull back.

[00:13:44] Too much nitrogen post-fruit set is going to push that plant back toward growing more foliage. Cucumbers and squash, same general principle, right? These crops need a mid-season nitrogen boost, but time it for after the plant has very well-established vines, and it's starting to set fruit regularly. You don't do this during that early initial flowering window.

[00:14:08] And then I want to flag something with zucchini specifically because a lot of gardeners are frustrated right now with early blossom drop. If your squash plants are producing flowers, but they're not setting fruit, more nitrogen is almost certainly not the answer, okay? Early squash produce male flowers first, then female flowers.

[00:14:34] So if you've only got male flowers, right now you're just waiting for the females. You'll know the females because they have that little proto-fruit at the very base of the flower, the little bulb, okay? That's what eventually becomes the fruit. So if you have both of those, but you have no fruit set, the culprit is most likely pollination, not nutrition. So adding nitrogen at this stage will make things worse, not better, by pushing more vegetative growth.

[00:15:01] Now for sweet corn, corn is the classic heavy feeder, okay? So this is one crop where nitrogen side dressing mid-season is almost always in the routine and where the timing is a little bit more straightforward. So, you know, it may need nitrogen fertilization or applications about every four weeks. So when your corn plants are about one-third grown, roughly about knee-high, right?

[00:15:31] You've heard that phrase, knee-high by the 4th of July, well, which is right around the corner. So, and if you planted your corn in May anyway. So if you've done succession plantings, this physical sign of, you know, how tall it is helps you determine when to feed each one of those plots. So, go ahead and do your side dressing at about the time that they are knee-high. Do not, however, broadcast fertilizer into the whorls of the corn leaves.

[00:15:57] It can sit there and it's going to burn the new leaves as they pop up. So you want to side dress alongside the row about four to six inches away from the stalk and then just water it in. The outlier here is our legumes. So our beans and our peas. These are the exception to most of this. Legumes have a relationship with soil bacteria that allows them to fix atmospheric nitrogen into a plant-available form in their root nodules.

[00:16:25] So your beans and your peas are likely generating their own nitrogen supply right now, especially if you inoculated them at planting. So pushing additional nitrogen on top of that leads to exactly what you don't want. Lots of leafy growth, which is going to delay the flowering and that is going to reduce our pod set. So if you're growing beans or peas and things look healthy, leave them alone. They do not need a nitrogen hit.

[00:16:57] So let's talk about the other two macronutrients because I glossed over them in favor of nitrogen and that's not the complete picture for our fruiting crops. Phosphorus and potassium both show up on every fertilizer bag. They are the second and the third numbers in that NPK sequence. And they both get marketed aggressively as things that you should be adding mid-season to get more flowers and fruit.

[00:17:24] So let me give you the honest research position on each one because they're actually pretty different stories. We'll do phosphorus first and this one might surprise you. Phosphorus supports root development and energy transfer at the cellular level and the plants transition from vegetative growth into flowering. These are real and important functions.

[00:17:48] But what the popular advice usually skips is that phosphorus doesn't leach out of your soil the way that nitrogen does. It binds to those soil particles and it accumulates. So a lot of home gardeners with any history of regular composting or fertilizing likely already has high to sometimes excessive soil phosphorus levels.

[00:18:14] When that's the case, adding more phosphorus mid-season does not help your plants. It can actually interfere with their ability to take up micronutrients like iron and zinc. And it can harm the beneficial soil microbes. So for most home gardeners, phosphorus is a pre-plant and soil building story, not a mid-season intervention.

[00:18:39] If you're working good compost into your beds before planting or at the end of the season to overwinter, and you've been doing that for a few seasons, you almost certainly have adequate phosphorus. The time to address a genuine phosphorus deficiency is at planting time, working it into the soil where the developing roots can reach it, not necessarily as a foliar spray or as like a mid-season side dressing.

[00:19:07] If you've never done a soil test and you're not sure, that is your sign to pull one. Your result may show that you don't need to spend money on phosphorus at all. And then one thing worth knowing about phosphorus, that purple or reddish tint on the underside of tomato or pepper leaves that sometimes shows up like in the late spring, that's often misread as phosphorus deficiency.

[00:19:37] And it is as far as the plant is concerned. But in most cases, at that time of the year, it's actually a phosphorus uptake problem. And that is caused by cold soil temperatures, which are slowing the root function. So it's not low soil phosphorus. It's just that it's not getting into the plant. Once the soil warms up, that fixes it. And you likely notice that because suddenly the undersides of those plants were no longer purple anymore. Right.

[00:20:05] And you didn't add any phosphorus fertilizer. Right. So there you go. And then potassium is where the fruiting crop conversation gets interesting. Potassium drives sugar transport into the developing fruit. It regulates how your plants manage water through their stomata. And it supports enzyme activity. And it's a major structural component of the fruit itself.

[00:20:34] So they've done the research. And the tomato plants that have adequate potassium levels, we'll use tomatoes as an example, have significantly fewer ripening problems. So things like internal whitening the white spots or the blotchy or uneven color on the outside of the fruit or yellow shoulders. Much better than plants that were low on potassium during that time when the fruit was sizing up.

[00:21:04] So those are more harvest time failures that go back to what was happening nutritionally weeks earlier while the fruit was sizing up. Potassium demand escalates really sharply once the fruit starts to get its size. Tomatoes, peppers, cucumbers, melons, they all have high potassium requirements during active fruit development.

[00:21:30] It is the nutrient that is most directly tied to fruit weight and flavor and color and even how evenly your tomatoes ripen. But here's the thing though. Just like phosphorus, potassium in your soil doesn't just disappear. It doesn't leach the way that nitrogen does. So for gardeners who are working in reasonably amended beds, potassium mid-season deficiency is less often a case of never adding enough.

[00:22:00] It's more often a case of something is interfering with the uptake. The research has shown us that even when soil potassium levels tested as adequate, heavy fruit load combined with reduced root function, whether that was from waterlogged soil or compaction or high soil temperatures, it can all create a potassium shortfall at the plant level. So that fruit is what we call a sink.

[00:22:28] It is a high demand place where all those nutrients are going. If the roots can't keep up, you're going to see it in the fruit quality. So if you've been amending your beds with compost, you are probably fine on potassium. Get a soil test to confirm, okay? Maintain consistent soil moisture because potassium uptake is strongly tied to water movement through the root zone, which also means avoiding compaction in the soil.

[00:22:56] We want to keep those roots functioning, okay? Those management practices are going to do more to support the potassium availability in the mid-season than throwing a top dressing on, you know, in most of our garden situations. Now, if you are genuinely, you know, in sandy or depleted soil, or your soil test shows that you have low potassium, then a mid-season potassium application might be warranted once the fruit is actively sizing up.

[00:23:26] Organic sources for potassium include things like kelp meal and green sand, but understand that they are both slow release. So don't expect immediate results. Wood ash also contains potassium, but this also raises the soil pH. So you want to use this cautiously if your pH is already in that kind of neutral to alkaline range. Now, if you need something fast-acting, I have used kelp as a foliar spray,

[00:23:54] and that works really well as something that gets into the plant where it needs to be right away. Potassium is very highly mobile in the plant. So if there's a problem with potassium uptake because of the soil conditions, using a foliar spray gets the potassium into the plant, and it can move to the fruit from there. We just have to remember, once our fruiting crops move into active fruit set and sizing, the nutrient ratio that they need shifts.

[00:24:23] Generally, this is lower nitrogen, higher potassium. That's why products are marketed as tomato fertilizer. They are kind of in a distinct category from your general purpose fertilizers, right? They're usually formulated with that developmental shift in mind. So you'll see ratios like 4-6-8 or 8-16-16 rather than that balanced 10-10-10 that we use for everything else, okay?

[00:24:50] So if you're using a balanced fertilizer on your tomatoes and your peppers through the whole season without adjusting, you're pushing nitrogen when the plant is trying to fruit and potentially under-supporting the potassium when it needs it most. Now, are you always going to see problems because of this? No, but having the knowledge when you go to choose a fertilizer or an amendment is important. So that's what I'm giving you, the knowledge. Do your best with what you have.

[00:25:18] The short version is that nitrogen builds the plant, okay? Potassium builds the fruit. Phosphorus is mostly a pre-planting conversation if you're already in an established garden bed. So get your soil tested. Are we sensing a theme here? Yes. Get your soil tested. Good. Amend before planting. Once your fruiting crops are sizing up, that's when to think about potassium, not more nitrogen.

[00:25:48] So before you grab a fertilizer and side dress anything, you should be reading your plants because deficiency symptoms and stress symptoms look very similar. And fertilizing a stressed plant is actually going to make things worse. So nitrogen deficiency shows up first in the oldest, lowest leaves. The yellowing starts there and it works upward.

[00:26:12] So if your tomatoes or your corn or even your leafy greens have very, very pale green to yellow lower leaves while that upper growth looks dark green, you're probably looking at your nitrogen running short. The other sign is a growth slowdown. So plants that were actively putting on size and then have suddenly sort of stalled, especially in mid-season when the conditions should be pretty ideal right now, usually they need nitrogen. Okay.

[00:26:39] But stalled growth can also be a symptom of root issues or soil compaction, heat stress, water logging, pests, all kinds of things. So this is where a soil test is genuinely useful because it takes the guesswork out. Phosphorus deficiency shows up as stunted growth usually, or like I mentioned before, a reddish purple tint in the leaf tissue.

[00:27:05] You're most likely to see this, again, in those cold soil conditions early in the season because phosphorus uptake is temperature dependent. So if you saw purple-tinged tomato seedlings in the spring, that was likely phosphorus uptake being limited by the cold soil, not necessarily a phosphorus deficiency in your soil. Again, take a soil test. Potassium deficiency. This causes browning at the leaf edges, and it's usually starting with those older, lower leaves.

[00:27:33] So if the yellowing or the browning is on the interior of the leaf rather than at the edges, that is likely not a potassium deficiency. Again, take a soil test. Okay? So what happens when the symptoms aren't what they look like? Damage from other stress factors like crowding, insufficient sunlight, compacted soil, root knot nematodes even,

[00:27:59] this can often look like a nutrient deficiency symptom. Okay? And this is what I see happening in these gardening groups all the time right now. So before you assume your plants are hungry, rule out all of those other causes. I've seen gardens where someone just kept adding nitrogen, trying to green up their plants, and the real issue was root damage from overwatering.

[00:28:26] So more fertilizer in a waterlogged root zone does not help. It makes the root environment worse. So we have to be sure that we are addressing the actual cause. And the cleanest way that I know to know what your soil actually needs is to test it. I swear to you, nine times out of ten, when I have a gardener describing their symptoms of their plants to me, and I ask them if they have ever taken a soil test, they look at me like I have two heads. And I get it.

[00:28:54] A lot of time, soil testing has only been talked about in terms of farming. But home gardeners really, really do need to know what they're growing in if they want to be successful. I actually got into a little bit of an argument with someone in a local group who was telling people it's not that serious when I recommended a soil test. But for some people, it is that serious. Whether you're trying to actually feed your family from your gardens or you're doing it as a hobby,

[00:29:24] wouldn't you rather have an understanding of what you're starting with rather than having to play detective every single time something looks off in the garden? It relieves a little bit of that stress, if nothing else, and it makes the process more enjoyable. A basic soil test from your state's soil testing lab will give you organic matter content, pH, phosphorus, and potassium levels. And their interpretation tells you what to supplement with.

[00:29:52] Worst case scenario, head to the garden center or your favorite online retailer and grab an off-the-shelf soil test kit. It's going to give you the levels of your big three nutrients and your soil pH, and it is fast and easy to do right there in your kitchen. I will link to my favorite one in the show notes. If your soil has high phosphorus and potassium already, which we've already determined is common in gardens that have been regularly amended with compost or manure,

[00:30:21] then you may need to use a nitrogen-only fertilizer rather than a complete fertilizer. Adding more phosphorus and potassium to soil that already has plenty doesn't benefit roots, and it may harm the beneficial soil microbes. If you've never done a soil test, I absolutely recommend getting a university test done at least once, and then using the off-the-shelf kit to check it like every year thereafter.

[00:30:49] The more frequently you test, the more it's going to remove a lot of the guesswork from these decisions that you're making mid-season, and it gives you a foundation for deciding what's actually wrong with your plant. It's not that serious. Go away.

[00:31:11] Now, I said to side-dress your plants with your chosen fertilizer, and I realize a large percentage of you looked at your podcast player and said, what does that mean, Karen? Side-dressing is the practice of applying fertilizer or an amendment alongside established plants after they're up and growing, rather than just kind of broadcasting it across the whole garden or incorporating it at planting time.

[00:31:37] Okay. It's the standard technique for a mid-season fertilizer application, and doing it correctly matters for both the effectiveness but also for plant safety. So for mid-season feeding, you have two main options. You've got granular fertilizers or liquid fertilizers. Granular forms are side-dressed. They are placed alongside the row and just worked lightly into the top one to two inches of soil and then watered in.

[00:32:04] I try to do this just before we have rain in the forecast so it can just be naturally watered in. Granular nutrients are released more gradually than liquid fertilizers, which means they are less likely to leach out quickly, but they are also slower to show results. So if you have plants that are clearly in distress and desperate for some nutrition, then you may opt for a liquid version. So your organic nitrogen sources include blood meal and alfalfa meal.

[00:32:33] These are both considered granular. And fish emulsion, which is a liquid. So the blood meal and the alfalfa pellets need to be lightly worked into the soil, and they take longer to show results. So if you're seeing obvious deficiencies now, you would consider pairing that with a faster release option. Fish emulsion is a liquid, and it gets taken up faster, but it needs more frequent application to maintain the same effect. So the solution to a bed of plants that are desperate for nitrogen right now

[00:33:03] would be to water in the fish emulsion near the roots, then follow up with a side dressing of alfalfa pellets, for example, on top to be watered in. The granular forms are more common for a mid-season application because we want this to last for several weeks. This is assuming that our plants are not in immediate distress. The key here is to side dress by placing the fertilizer

[00:33:29] either around individual plants or along the sides of rows, but not directly against the stems. Fertilizer granules sitting on plant tissue can cause burn, so you want it about four to six inches away from the stems and the crowns of the plants. Now when you're using a liquid plant food or fertilizer, you want to make sure that you dilute it to the recommendations on the package, and then you're just going to apply it near the base of the plant where the roots are, but again, not up against the stem.

[00:33:58] This should be done when the soil is moist but not waterlogged, and we want to do it in the early morning during the summer so we avoid heat stress on the plants. Do not water with liquid fertilizer when the soil is dry or the plant is wilted because this can cause root damage and it can also reduce the nutrient uptake. So if the soil is dry, be sure to water first and then apply the liquid plant food. You also want to make sure that you're moving any mulch aside before you're applying any of these

[00:34:28] and then replace it afterwards. You want the fertilizer to actually reach the soil, not just sit on top of the mulch where it's going to be slow to reach the roots. Nitrogen is highly mobile once it's dissolved. It's going to move into that root zone pretty readily with irrigation or rain, which is part of why side dressing works even just at the soil surface. Now, how often you do this is going to depend on the crop and what you're seeing. So Missouri Extension actually has a tomato guide,

[00:34:55] and they recommend three side dressings in total throughout the season. So the first one would be when that first fruits are about one-third of the way grown, and then the second one would be about two weeks after picking the first ripe fruit, and then the third one about a month later. That sort of spaced timing supports what we see as a long-season crop in tomatoes without pushing excessive vegetative growth between the applications.

[00:35:25] Now, for corn, the recommendation is a side dressing. Again, like we said, when the plants are about one-third grown, you can potentially add another one before the tasseling starts. But again, this should be based on a soil test. And then for those heavy harvesting leafy crops like the kale and the shard, that can mean an application about like every four to six weeks throughout the growing season. Watch how your plants grow to gauge their need for additional fertilizer.

[00:35:55] Response to nitrogen sources normally happens within about a week after application if they have adequate soil moisture. So you can gauge whether an application was needed by just watching the plant's response. That makes more sense than just keeping to like a calendar schedule. So when should we not fertilize? The first thing is don't fertilize a stressed plant, okay,

[00:36:24] because it needs all of its reserves to survive that stress. If your plant is dealing with heat stress or drought stress or waterlogged roots or an active pest or disease pressure, fertilizing does not help, okay? The plant can't use the nutrients effectively when it's in a stress response mode. And so forcing nutrient uptake into a damaged root system can actually increase the stress and increase the injury.

[00:36:51] So we want to stabilize the stress first. We want to, you know, get our soil moisture levels to where they're more appropriate. Address that pest or disease issue, right? And then once the plant is recovering, you can consider whether a light side dressing would be helpful or not. The other thing is to not fertilize before fruit set on fruiting crops. And I covered this in the fruiting crop section, but I'm repeating it here because it is important.

[00:37:17] Nitrogen pushed onto tomatoes or peppers or squash during that flowering and early fruit set window drives vegetative growth, which is going to delay or reduce that fruit production. We want to wait until the fruit is actively getting bigger. You also don't want to rely on more fertilizer to fix a non-nutrient problem. So blossom drop, poor fruit set, slow growth, leaf discoloration.

[00:37:47] All of these can look like a fertilizing problem, but they frequently are not. Blossom drop in tomatoes and peppers is almost always a temperature issue, okay? Night temperatures below 55 Fahrenheit or daytime highs above 95 Fahrenheit. These both prevent pollen viability and they cause the flowers to drop. No amount of fertilizer can fix a temperature problem.

[00:38:12] Root damage from overwatering or torrential downpours, I'm sorry, like what we've been having. Soil compaction, any soil-borne diseases. These also affect nutrient uptake, but not nutrient availability, okay? That's a very different thing. The nutrients can be available in the soil, but not able to be taken up.

[00:38:36] More fertilizer in a root-compromised situation does not help, and it's often going to do more harm than good. A soil pH that is either too low or too high, that locks up nutrients too on a chemical basis. So it makes them unavailable regardless of how much you put in there. So before you fertilize, ask, is the soil moisture right? Is the pH in range? Are the roots healthy, right? Is there a disease or pest pressure at work here?

[00:39:03] If the answer to any of those is no or I don't know, start there. And then just remember, you know, fertilizing is not insurance, okay? More is not better in terms of either the frequency or the dosage. And extra nutrients will not necessarily stay stored in the soil for future root absorption, especially when we're talking about nitrogen.

[00:39:30] Over-applied nitrogen in particular can increase vulnerability to pest and disease pressure, okay? And then it also leads to leaching, and that pollutes our groundwater, okay? So one to two pounds of a balanced fertilizer per 100 feet of garden row is like a general maintenance rate. That's a modest amount. The instinct to just give a little more is usually the wrong instinct in a vegetable garden.

[00:40:03] So go walk your garden today and pick one bed or one crop to take a really hard look at. Look at the oldest, lowest leaves first. Is there any yellowing there? Look at the growth rate. Has it stalled out? Look at what stage of development that your fruiting crops are in. Are they flowering? Are they at the fruit setting stage? Is it, is the fruit sizing up?

[00:40:27] Let that assessment tell you whether a fertilization is warranted, and if so, when. If you've never done a soil test, this is also a good time to do one. Your state's extension program offers soil testing. Here in Missouri, that's University of Missouri Soil Testing Lab, okay? The results will tell you what your soil actually has and what it actually needs, so you can stop guessing.

[00:40:54] At the bare minimum, go ahead and grab an off-the-shelf kit and do your own test. The research on mid-season fertilizing says that timing matters more than quantity. The crop type determines the timing. And the most common mistake in June isn't that gardeners are under-fertilizing. It's that they're fertilizing at the wrong time or in response to problems that fertilizer can't fix.

[00:41:25] Until next time, my gardening friends, keep on cultivating that dream garden, and we'll talk again soon. What are the best ideas that you'd be doing? I guess a lot of Kalau rootsuliflower and comer for that, it's very significant. Thanks for that. You're going to see Bonusman and steal segments.