Rhubarb, Asparagus Beetles, Fertilizer, and Other Gardener Questions - Ep. 150

Karin Velez [00:00:00]:

We are almost into June and peak gardening season for much of the Northern hemisphere, which is also peak time for gardening Questions welcome back, my gardening friends, to another episode of Just Grow Something. If you're new here, welcome to the podcast that answers the why behind the how of so many gardening tasks, and that includes some of today's topics. I am in multiple garden in groups on Facebook, including ours. Shameless plug for the just grow something gardening friends. Facebook group. Plus, I'm at the farmers market every weekend, and I'm an open resource via email and instant messenger, so there are a ton of ways for people to ask me their gardening questions or to ask groups of gardeners in general. Each one of those questions doesn't necessarily need an episode of its own, but I thought I'd put a few of them together that I've seen or gotten directly over the past few weeks. Because if one person has the question, it's likely there are a boatload of us that also have the same question.

Karin Velez [00:01:04]:

I've also got an observation, one that will lead to an attempt to keep certain critters out of certain garden areas. For me, that will specifically be deer and raccoons out of my tomatoes. But for a fellow gardener that had the same observation, it's squirrels out of her garden in general. Either way, it's a little something that may be of interest to you if you're in an area facing a drought this summer or just very dry conditions that may help keep those critters from taking a bite out of your harvest. Let's dig in. This is your last chance to get entered into the 50K giveaway to celebrate 50,000 downloads of this podcast. You can do that by leaving a review just like this one from lovely Lisa Zero on Apple podcasts titled Love the Science of Gardening. And she said, I love the way Karen explains the science behind gardening.

Karin Velez [00:02:01]:

Great podcast. Well, thank you, Lisa. It makes me very happy to hear that there are other people out there like me that don't just want to know how to do something, but also why it works. I think that makes us better gardeners overall and helps us problem solve much more effectively in the future. Thank you for those kind words, Lisa, and you are now entered into the giveaway. Now, if you've not left a review on Apple podcast, Audible Pod Chaser, Cast Box, or anywhere that reviews are offered, you have until May 31, 2023. That's tomorrow. To do that to be entered into the contest, be sure that you message me if you leave it anywhere other than Apple.

Karin Velez [00:02:40]:

You also have the option to share an episode of the show in your social media and tag me in it as another entry like Adventure Seeking Mama did on her Instagram. Or you can email me or direct message me a note about what you like about the show or how it has helped you in your garden, that's the third way you can be entered. Just like the listener that messaged me not only saying what she likes about the show, but asking a question. And part of that question is where we'll start this week's question and answer session with asparagus beetles. If you're unfamiliar with asparagus beetles, there is the common asparagus beetle and the spotted asparagus beetle. Now, the adults both feed on asparagus spears and cause them to be browned and scarred. Both types of the asparagus beetles are about quarter inch long. When they are adults, they have oval shaped bodies with sort of mid length antenna.

Karin Velez [00:03:37]:

The common asparagus beetle, when it's adult, is a bluish black with six cream colored spots on its back. The adult spotted asparagus beetles are reddish orange with twelve black spots. Now, common asparagus beetles will overwinter as adults in any place they can get shelter under loose tree bark or leaf litter or other plant debris, or in the hollow stems of the old asparagus plants. The adults will appear in the garden just as the asparagus spears are coming out of the soil in the spring. So they're going to lay dark brown, oval shaped eggs in rows on either the spears, the ferns, or the flower buds of your asparagus plants. Those eggs will hatch within about a week, and then the larvae move to the ferns to start feeding. They'll feed there for about two weeks, and then they fall to the ground to transform into pupae in the soil. And then it only takes about a week for those adults to emerge to start another whole generation feeding on the ferns for the rest of the growing season.

Karin Velez [00:04:46]:

Now, the spotted asparagus beetle, that's the reddish orange one with the twelve black spots, has a similar life cycle, but it's shorter. It usually appears in the gardens later than the common asparagus beetle, and it's usually gone by around late July. They lay greenish eggs on the ferns, and then they have an orange larvae that feed on the berries of the asparagus. Now, all of this is important to know because knowing the life cycle and the timing of these pests means we have a little bit more information about how to combat them or counteract. So if you've had asparagus beetles in the past, it is very important to clean up any garden debris at the end of the season, including pulling those old ferns. This eliminates some of the places the adults will try to winter over. And then in the spring, as soon as you start to see those beetles or their eggs, pick them off by hand and drop them in a pail of soapy water to dispose of them. You're going to have to be vigilant and do this every single time that you are in the garden.

Karin Velez [00:05:48]:

This is one way to reduce the adult population while also eliminating the eggs so that you can help to break that life cycle. And also, if you've got the spotted beetle, be sure that you're not allowing your asparagus to produce berries, so the larvae will have less to feed on. Now, you may notice a tiny metallic green wasp flying around. These are tetrastychus asparagi. It's a parasitic wasp that is specific to asparagus beetles. These wasps will inject their eggs into the asparagus beetle eggs, and so the wasp larvae is going to live and feed inside the beetle eggs. They can kill up to 70% of those beetle eggs if they're present in your garden, so keep an eye out for them. Lady beetle or ladybug larvae and other insect predators may also be around, and they will also eat both the eggs and the larvae of the asparagus beetle.

Karin Velez [00:06:44]:

Which is why we should try to avoid using any insecticides for control if we can give the good bugs the opportunity to do what they do best. And if you have chickens, pen them up in your asparagus patch at the end of your harvest. They'll make short work of those beetles and anything else, and their larvae, and they'll fertilize the crop at the same time. But if you do end up with an infestation that is just out of control, you do have a few insecticidal options. Neem oil can be used by coating the oil on the spears once you've completed your harvest. You can also do this very early in the season, as soon as the spears emerge. If you know you had a bad infestation the previous year, this is effective for just a few days, though, and so you will need to apply it again. Spinosat is another one that's effective.

Karin Velez [00:07:31]:

It's effective for about a week, and then we get into the permethrins that are effective for about two to three weeks, but they are definitely stronger and they are very toxic to pollinators. And honestly, any insecticide is. So be sure that you are applying these in the very early morning or the late evening, and not when other plants in the area are actively flowering, so that we avoid the spray drifting and causing harm to the good bugs in the garden. And even though all the pesticides I've mentioned are naturally derived, you still need to follow the directions specifically and not over or under apply for your safety, the safety of your garden, and to avoid creating insect strains that are resistant to the application. So please make sure you are following the directions, because on any insecticide, the label is the law. Now, if you don't see the beetles themselves, you'll still know if you have a problem with them by looking at your plants. Asparagus spears are going to become brown and they're going to bend over into a hook shape, kind of like a shepherd's hook, when asparagus beetle adults are feeding on the spears. Now, because the spotted beetle appears later on in the season, it doesn't often do actual damage to the plants.

Karin Velez [00:08:49]:

They're just really unsightly. But the common beetle can do damage not only to the harvestable spears, but so much to the plants themselves that it can reduce the ability of the plant to store enough energy for next year's harvest. So early control is in your best interest with asparagus beetles. Next up, we have a question about fertilizer numbers. This came from one of the Facebook groups I'm in, and the gardener was wondering what the difference was in the low numbers on fertilizer containers and the higher ones. Specifically, she wanted to know what the difference was in a fertilizer that was listed as a five four five versus one, that is a 1510 15. So lower numbers in fertilizers are often associated with what we call bio based agrochemicals or natural fertilizers. Fish emulsion, backuano, blood meal, bone meal, feather meal, chicken manure, those types of things, right? And the higher numbers are often synthetically derived or synthesized chemical versions of the nutrients.

Karin Velez [00:10:04]:

So things like ammonium nitrate or potassium sulfate, these are manufactured from natural ingredients like phosphate, rock and sodium chloride, but they are refined to be made much more concentrated, hence those high numbers. Now, most of these processed fertilizers are quick release in a water soluble form to deliver nutrients quickly to the plant, unless they are intentionally created to be slow release. The numbers themselves on the containers represent the percentage by weight of each one of the nutrients in that container. Okay, so if we have a ten pound bag of a granular fertilizer and it is labeled five four five, that means the bag is 5% nitrogen, 4% phosphorus, and 5% potassium. Okay? Those numbers always go NPK, nitrogen, phosphorus, potassium. So in other words, if you were to spread that entire bag on your 100 square foot garden, you'd be adding a half a pound each of nitrogen and potassium and 0.4 pounds of phosphorus. Now, comparatively, if you used the bag marked 15 10 15 over the same garden area, you'd be adding one and a half pounds each of nitrogen and potassium and one full pound of phosphorus. So over a small area, that's a really big difference, especially if you're not particularly deficient in any one of those nutrients.

Karin Velez [00:11:49]:

So this is one of the reasons why a soil test is important before we start adding fertilizer to the garden. It is very easy to overdo it, especially with nitrogen, and that can cause adverse effects to our plants. I think the only thing that's worse than an underfed plant is an overfed one, and sometimes the overfeeding can actually be more damaging. The other thing about this is fertilizers that are chemically derived are created to be more readily absorbed by the plant. And if it's not taken up, those nutrients aren't taken up. The soil can't really do anything with it. The microbes in the soil have no use for these forms of nutrients. And so any excess that's left behind that's not been taken up by the plants is going to leach out of the soil into your watershed and contribute to water pollution.

Karin Velez [00:12:40]:

Overuse of these types of fertilizers can also lead to overgrowth in your plants, which causes production issues in our garden. If you use too much of a nitrogen fertilizer, your plants are going to see an explosion of green leafy growth, which might be fine at first. They're going to look super healthy. But if that nitrogen continues to be taken up by the plant at the same rate at the same time, it should be blooming and producing fruit. Well, it's not going to produce. You'll have a bunch of leafy growth and no flowers. If it's a brassica that forms a head, it won't do that either. It will just to continue to grow leaves.

Karin Velez [00:13:21]:

Now, interestingly enough, the amount of fertilizer needed by our garden plants decreases in direct proportion to the amount of organic matter increasing in the soil. Okay, think about that for a second. The higher the amount of organic matter that is in our soil, the less fertilizer our plants are going to need, because they are garnering all of the nutrition that they need from that organic matter. So adding those amendments like compost, spent mushroom blocks and worm castings, or amendments derived from those types of things, is going to feed the soil, not just the plants. And the soil, in turn, continues to feed the plants over the long term, which means we eventually use less of these things. So good plant health depends on our plants having a continuous supply of available nutrients from the soil, or in the case of container growing, whatever growing media you are using. Now, plants should get their nutrients from the minerals and the organic matter in the soil first, and that soil should be amended with compost and other organic matter every season to maintain that fertility. Added fertilizers should be our second course of action in times when our soil tests say that we're deficient and our plants are showing signs of problems, or when we're growing in containers and the nutrients are being used up at a faster rate because there is a lower soil volume.

Karin Velez [00:14:51]:

So nutrient needs are going to vary from plant to plant, and the ability of our soil to supply those nutrients is going to vary. But let's not forget that there are actually 17 essential elements required for plant growth. And nitrogen, phosphorus and potassium are only three of those. Granted, they're the big three, but besides carbon, oxygen, and hydrogen, the remaining secondary and trace elements need to come from somewhere, and that's usually the soil. So even our containers should have some organic element like compost added at the time of planting. Now, one other thought about the low numbers that you will see is that you will also see this on liquid fertilizers often, regardless of how the nutrient is derived. And this is because you've got a nutrient concentration that is immediately available to the plant roots in a liquid form and can be taken up very, very quickly. It doesn't need to be dissolved into the soil water space like a granular fertilizer does.

Karin Velez [00:15:57]:

So this means the effects can be seen very quickly, but it also means it's very easy to overdo those nutrients. So liquid nutrients are often meant to be used in smaller doses more frequently and it's usually meant to be mixed with water. Before application again, read the manufacturer instructions. The meaning of the numbers, though, is still the same even if it's in a liquid form. So if you have a 16 ounce bottle of liquid fertilizer and it is a five four five, then that still means that 5% by weight of that bottle is nitrogen, not volume weight. So it's very important to follow manufacturer recommendations when using a liquid fertilizer and be sure you're diluting it correctly to avoid overfeeding the plants all at once. Finally, we have the Rhubarb question. This one also came from a Facebook group and the gardener asked why his rhubarb wasn't turning red.

Karin Velez [00:17:01]:

So this can actually be for one of two reasons. The first being it's not a variety that turns red. So if this is a new plant to you, it is very possible that the variety that you chose is one that actually stays green or some combination of red and green. I actually had a green one and waited and waited for it to turn red and it did not. And it turned out to be a variety that was a green variety. So some red varieties include Ruby, McDonald, Valentine, canada Red, crimson Wine, Cherry, red Strawberry and Hardy Tardy. And some of the green varieties are things like German Wine which actually has green stems with pink speckles on it, turkish and Sutton's seedless. There is one called the Sutton, which is green, and red streaked Sunrise which is pink.

Karin Velez [00:17:55]:

In general, the green stalked varieties also tend to be much larger with thicker stalks than the all red types. Now, the variety that I had was Victoria, which is red at the very base, but mainly green the rest of the way up when I thought I was growing Victoria red, which is fully red throughout. So if this is your first year growing your rhubarb, double check to make sure that it's not a green variety if you're concerned that it's not turning red. Now the second consideration could be your soil PH. If the soil PH has dropped too low, meaning it is too acidic, anything below, say 6.5 or six, the coloring of the plant will be affected and it may not actually turn red. So you're going to want to do a soil test and then amend accordingly. Now, the good news about this is this coloring change or lack thereof, doesn't actually affect the ripeness of the plant. So you can still harvest the rhubarb at the appropriate size and time and know that it is actually ripe.

Karin Velez [00:19:03]:

But if you do have a PH issue, then yeah, that's going to keep it from turning red like you would expect. And now here's an interesting anecdote from one gardener who was facing a problem with squirrels in her garden. She said that every day she would come out to water and something would be dug up or destroyed. So she placed some saucers of water around her container garden and the squirrels have not touched anything since. She's guessing that the little guys were just thirsty and they were seeking out water. Now we had this exact problem in our tomato field last year. Some of you may remember we talked about it. We were in a severe drought here, and the night before I planned to bring in our first big harvest of ripe tomatoes.

Karin Velez [00:19:52]:

The deer and the raccoons went through that field and stripped those plants of every last tomato, ripe and green alike. There was not a tomato left to be seen in that entire field. And it was six weeks before those plants recovered and started producing tomatoes again. And the best we could figure at the time was that they were looking for moisture. So like this gardener that I was talking about, I'm trying to come up with a plan to provide the wildlife with hydrating foods and water troughs of some sort this year. I mean, they have a creek, Wolf Creek, that runs right through our farm that they have full access to, but when the creek level gets low due to a drought, I guess the animals just get desperate. I'm not exactly sure what our plan is yet, but we need to decide on something soon because we've only had about two inches of rain here over the past six weeks and it doesn't look like it's getting any better anytime soon. So we may be in for another tough gardening season in west central Missouri, and I don't need the wildlife adding to the problem.

Karin Velez [00:21:00]:

So if you garden in a hot, dry area and have had some critter problems in past seasons, try putting some water out and see if that doesn't help deter them from digging in your veggies. That's it for today. If you have a gardening question I can answer, feel free to message me on social media or send me an email to grow@justgrowsomethingpodcast.com or jump in the Justgrowsomething Gardening Friends Facebook group and we'll get it answered for you and maybe for everybody else listening. Until next time, my gardening friends. Keep on cultivating that dream garden and we'll talk again soon.