How to Tackle Mid-Summer Fungal Diseases - Ep. 261

Karin Velez [00:00:00]:
Have you ever strolled out into your garden, coffee in hand, or maybe cocktail, and suddenly noticed that your beautiful cucumber plant looks like it was dusted in powdered sugar? Yeah, that fluffy white coating is powdery mildew. And it is the uninvited guest that keeps showing up to the garden party. So today we're diving into the sometimes mysterious but always annoying world of fungal diseases. Powdery mildew, blight, leaf spots, all the fun things. These issues are not just cosmetic. They can actually seriously affect our plant's productivity and the health of the plant if we let them go unchecked. So today on Just Grow Something, we are going to break down exactly what causes these issues, how to prevent them, and how to treat them organically and effectively using both homemade and store bought options. We're going to talk milk sprays, pruning for airflow, cultural controls, and more. Let's dig in.

Karin Velez [00:01:22]:
So part of the reason that we're doing this episode this time of the year rather than in the spring is because it has been a very, very rainy season. Unusually so for a lot of us here in the US and these fungal diseases in the mid summer time frame are not usual for us, especially here in west central Missouri. We are very used to having a cool and wet spring and that's usually when these fungal diseases are starting to try to run rampant and we really have to keep an eye on them and keep them under control. But in most instances, once we get to about the middle of July, Mother Nature has turned the faucet off and the sun has come out to try to cook us. And that means that the plants have a chance to dry up. Even though we will still have a high level of humidity throughout the summer, the summer we still get those suns raised to help sort of cook a lot of this off. What we're experiencing this year is very different from most seasons. We have had such a rainy July. I mean we had a very rainy spring to begin with and then we continued into to June and now all the way into the end of July and now into August. It's just been Insane. The amount of rain that we have had, so our usual humidity has been even higher.

Karin Velez [00:02:45]:
The plants aren't really getting much of a chance to dry out in between these rainstorms. So if this is something that you are experiencing, you very well may be finding that you are having higher instances of these fungal diseases in your garden right now, which is not usual. So what are we up against here? Fungal diseases come in a lot of forms, but some of the most common and most troublesome ones for us as home gardeners are things like powdery mildew, leaf spot diseases, and blights. So powdery mildew looks like a white powder on your leaves, and it thrives in warm, humid conditions with poor airflow. The next one is those leaf spot diseases. These show up as black, brown or yellow spots that can cause premature leaf drops. So think septoria leaf spot and then blight. So tomato blight or potato late blight.

Karin Velez [00:03:45]:
These are very serious and they can actually wipe out plants in a matter of days. Most fungal pathogens love wet leaves. So if your plants are not getting the chance to dry out in between rainstorms, this is the perfect place for these fungal pathogens to just latch on and hold on. They also love very crowded plants. So if you've made an attempt at interplanting this year and there's not enough airflow in between those plants right now, those plants may be experiencing some sort of crowding conditions, poor air circulation that goes along with the crowded plants, and then nitrogen overloaded growth. So if you have been feeding your plants, but what you're feeding them is high in nitrogen, and they're getting a lot of that really good green leafy growth, that nitrogen overload can actually attract fungal pathogens. A lot of these pathogens will actually overwinter in plant disease or in plant debris. And so the diseases that are showing up actually mean that last year's issues have become this year's issues, especially if we're not careful and we don't pay attention to what's going on.

Karin Velez [00:05:04]:
So one of the ways that we can treat these fungal issues is just by essentially changing the ph of the leaf surface. So one of the easiest ways to do this with just stuff that you have in, in your house that is very lowcost and also impacts, you know, highly, is milk spray. Yes, milk. Like moomoo juice milk, cow's milk or goat's milk, even whatever. Studies have shown that a very simple 10% solution of milk and water, so it's 1 part milk to 9 parts water, can be Just as effective as controlling or at controlling powdery mildew as synthetic fungicides. So I mean, you could make it higher than this. Some gardeners go as high as 40%. But essentially, not only are we kind of changing the PH of the leaf surface at this point, but the proteins in milk react with sunlight.

Karin Velez [00:06:11]:
So that creates compounds that basically fry the fungus. It's like an organic little laser beam. It's just, you know, burning it off. So this is something that you could spray on your plants about every, you know, week to two weeks or so during really humid weather. You would want to do this either at the very first sign of that powdery mildew coming on or even beforehand if you know that this is something that you're going to end up dealing with. Right. Whole, whole milk works best and you're going to want to apply it in the morning so the leaves dry very quickly during the day. Day.

Karin Velez [00:06:51]:
Another homemade solution would be baking soda. Now be careful with this because too much baking soda can actually cause leaf burn if it starts to get too hot outside. So again, you can mix this, you mix the baking soda with the water, but just start light and test it on a few leaves before going wild over the entire thing. Neem oil also helps in, in this instance. So same thing though, too much of the oil in like the wrong weather can actually cause leaf burn. So just know that, you know, you're going to be putting this on in the early part of the day and hoping that it is dry before the sun's rays start to get strongest at between, you know that like 10am and 4pm or, or at least noon and two time frame. Right? So always test these things very, you know, simply or very minimally before you move on to spraying the entire plant. Now there are store bought organic options for this because honestly, sometimes homemade just doesn't cut it.

Karin Velez [00:07:51]:
If you have a really, really tough infection with any of these things, you might want to look at organic fungicides. So sulfur and copper based fungicides are approved for organic use and they can both prevent and suppress a wide range of fungal issues. My preference is for the copper spray. I generally start spraying my tomatoes early in the season, even in the spring. So basically right as our spring rains sort of start to die off is when I normally start spraying for copper or spray the copper spray once every week to 10 days, depending on how humid it's been and how much fungal pressure I am seeing. Normally I will start to see that at the base of my tomato plants. I'll start to See, usually it's the, the blight or the septoria leaf spot. You'll start to see yellowing leaves and the spots on the leaves.

Karin Velez [00:08:50]:
That is a good indication that I've got some fungal stuff going on. But if I start early enough, it prevents it from taking hold. And if I continue to use it, then it's going to help suppress those fungal issues. Now, this year has been a little bit different because you're relying on that copper spray or that sulfur spray to stay put, right? But if it doesn't stop raining, then it can't really stay put. So, you know, I have gone out twice this season earlier in like the late spring, early summer when I would normally. First, I skipped the first application because it was still raining. There was no sense in me going out there and trying to spray anything. But then the second time I went out, I thought I had timed it pretty well and I went out and I sprayed all of my tomatoes and I pulled off the lower leaves to make sure that, you know, that, that anything that was on those lower leaves wasn't spreading.

Karin Velez [00:09:44]:
Sprayed everything down and quite literally, I think it was 12 hours later we had a torrential downpour. And I know that all that copper spray was just washed off. I, I have not gone back out and used it again. What I am using is first Saturday lime. And I've talked about this product before. It is a really good filtered lime product that is not water soluble. So that's good news. Unlike like if we're using it for pest issues, people will use like diatomaceous earth.

Karin Velez [00:10:16]:
But if you use the first Saturday lime number one, it's going to change that ph because it is, it is a lime, right? So the ph is going to be much higher than what the fungal diseases like to attach onto. And you can do a coating of this and you won't have to reapply it as frequently if you get some rain. Now, if you are getting a deluge of rain like what I have been getting, then it's nothing is going to hang on, right? And you're still going to have to go back out there. But I have found it to be a bit more effective this year just based on the amount of rain that we've been getting. So that is something that is another, another option for you. There is also potassium bicarbonate. You can find this online. You sometimes you can find them in, in the garden centers or maybe in an ag store.

Karin Velez [00:11:12]:
It is very similar to baking soda, but instead of being sodium bicarbonate, it's potassium Bicarbonate. So it is formulated to be gentler on the plants and a bit more effective. So this is something that you would want to try. I will say always, always read and follow the label for anything that it is that you'. The other thing you want to do is rotate what it is that you are using to prevent any kind of resistance from building up. Because these fungi are, these are living organisms and they can adapt the same way our insect pests can adapt to something. So how that adaptation works is if you're spraying something and it knocks down 90% of the fungus, but then that 10% of the fungus starts to reproduce. Well, the ones that are reproducing are the ones that have shown themselves to already be sort of resistant to the fungicide that you are using, whether it's a store bought version or it's milk or whatever.

Karin Velez [00:12:10]:
And so when you come back through and you knock it down again, then Maybe it's only 80% effective and the 20% that remains continues to reproduce. So that's, that's how our resistance gets built up. So if you can alternate what it is that you're using. Right. So go out there the first time and use the milk spray and then the next time come back through and use a copper spray. And the third time you come through, you use say the, the potassium bicarbonate or you do a baking soda mixture, whatever, change it up to where if it wasn't 100% knocked down the first time, whatever was remaining that was resistant to that first attempt is now being knocked out by something completely different. Or the third thing that you use knocks it out, that's going to help to prevent resistance from building. Okay.

Karin Velez [00:12:57]:
You also want to apply them as a pre preventative if you have had recurring issues, which once again is where your garden journal will come into play here. Okay. You're not going to know or remember a lot of the time. Now, if you've been doing this for years like I have, and you know, I mean, you've dealt with it year after year after year. Yeah. Then it's finally kind of drilled into your brain that, oh, I really have to get out there and take care of this before it becomes an issue. But if you are new to this or if this is a new issue for you, make sure that you are taking notes so that as you sit down and try to make your garden plan in the off season for next spring, you have these notes in front of you, which means you can put things on the calendar to remind you this is a time that I need to go out and I need to start doing some preventative measures for the fungal diseases. It's on my calendar for the season at the date that I need to start and I just put spray copper.

Karin Velez [00:13:55]:
That's all it is. Or spray tomatoes. I can't remember which one it is. I think I said spray tomatoes. And that tells me that oh yes, I have to get out there and start doing it. And then make a note on your calendar of when you did it so that seven to 10 days you can go back out and do it again. 14 days. Whatever it is, don't wait until you see that this is an issue that has like latched on before you start doing anything about it.

Karin Velez [00:14:19]:
Because these fungal diseases will spread super, super quickly, especially in this type of an atmosphere where we're constantly getting these rains and stuff. So do your due diligence and use them as a preventative or as soon as you see the problems rearing their ugly head

Karin Velez [00:16:10]:
Now let's also not forget the basics right Fungus loves moisture and congestion so we want to Worry about our airflow, our spacing, our cultural control. So here's what you can do. The first thing is to prune. Okay? If, even if you're not somebody who prunes on a regular basis like me, I've. I make no bones about the fact that I generally don't really prune, Prune my tomatoes very heavily. I only prune like the bottom 12 inches or so, only because I know that I have these fungal issues that come up every single year. And so keeping those, that, that airflow going at the bottom of the plant, number one, it's reducing the ability for any of the soil to splash up on those lower leaves. And that can transfer disease. Even with a heavy layer of mulch, that can still happen. So I make sure that I'm pruning all of that off.

Karin Velez [00:17:03]:
But it also keeps anything from, you know, it keeps the airflow going, and that is going to increase the airflow all the way through all the plants. And that helps. You can do this with most of your plants, your cucumbers, your zucchini plants, the lower leaves oftentimes are going to start dying off anyway as the production of your plant continues. So if you're paying really close attention and you're looking at like, say, your zucchini plant plants, right, you will see where the current fruiting point is. So as. Because essentially, you know, squashes, even your, your bush varieties of squashes, are still essentially a vine. And so as the fruiting point sort of moves up that plant, the leaves underneath those fruiting points start to die off. They will yellow.

Karin Velez [00:17:52]:
I get messages all the time from people going, oh, my gosh, what is wrong with my plant? These lower leaves are turning yellow. Yes, they're turning yellow because the plant doesn't need them anymore. So as soon as you see that start to happen, you can start to pull all of that foliage off of those plants. This goes for your cucumbers, your squashes, your tomatoes, lesser extent. I mean, yeah, you can do this with peppers too. I haven't had too much of a problem with these foliar diseases in my peppers. But if you do have this problem and you see that the lower leaves are starting to die off again, anytime we see the 3Ds disease dead or dying, continue, okay, we want to get it out of the garden. Out of the, out of the garden.

Karin Velez [00:18:29]:
So that pruning from the bottom is your first step. Staking or trellising to lift your plants up off the ground is also a really good idea here. The first few years That I gardened. I didn't intentionally trellis my cucumbers. They happened to be planted near something that they used as a trellis. So that very first garden in my suburban backyard, I had put up a piece of lattice to sort of block off that back corner. And the cucumbers naturally gravitated towards that and climbed up and through and over and intertwined in and around that lattice. And that wasn't something that I had planned.

Karin Velez [00:19:09]:
The next few years when we moved to the five acre homestead, I had planted them along a chain link fence that was up against where we were housing our chickens. And again, they naturally climbed up, but they also naturally climbed or grew out away from the base of that fence as well. And that I think was when I first started to notice that the plants that were up on the fence essentially trellised were, seemed to do better. I had less instances of diseases in those fruits and in those plants than I did the ones that were crawling across the ground. Now that I know better, obviously it makes sense because there's better airflow around those plants that are up off of the ground. You also don't have the fruit in contact with the ground because any, anywhere that fruit is contacting the soil, it's going to cause some soft spots. You have more of a possibility of a transfer of fungal pathogens and stuff. And that aquatic, of course, can lead to it getting onto the plant and then it continues on and up.

Karin Velez [00:20:14]:
This is not to say that you can't grow cucumbers and squashes and everything else just sort of on the ground. I would prefer if you had a really heavy layer of like straw mulch or something in between there. But even in that instance, if it's raining constantly, your mulch is going to be wet. So those plants are going to be in contact with that moisture. So if you are seeing that you are having issues with fungal diseases, this might be your opportunity to say, okay, I should be staking these things up, or I should be doing some sort of a trellis to help lift those plants up off the ground and further increase that airflow to make them just a healthier plant. The other thing, when it comes to airflow, is spacing your plants properly so that they're not kind of elbowing each other for room. Now this sounds a little counter to what I normally preach in terms of air interplanting, but I will say there is a little bit of a line that we walk where we have, we have inter cropped all of our plants to take the most advantage of the space that we have and to allow those plants to sort of support each other and, you know, feed off of each other for. For lack of a better term, and placing them too closely together to where they just don't have enough room and they don't have enough airflow flow.

Karin Velez [00:21:33]:
And, you know, this is another case for keeping a garden journal where, okay, maybe you tried interplanting for the first time this year, or maybe you got a little bit more aggressive about it and you put more plants into your same space. How are those plants faring right now? What do they look like? Do they seem like they're struggling? Are you having more instances of fungal diseases? Is that because it is super rainy in your area right now? Or are you having your normal weather conditions and you're seeing more fungal diseases? These are things that you put into your garden journal so that you can go back in the off season and look at that and understand when you start to plan next year. Oh, or even if you don't plan at all, at least when you go to plant next year, you can go in, like, and look at your notes and go, okay, maybe they were a little too close together. Let's maybe give them an extra inch all the way around this season and see how they go. Once you have a couple of years of notes, then you can start to develop a plan that says, okay, I know exactly how far I can push the envelope with these plants. Now, if you also are doing this and you know that this year is different for you and it is more rainy than it normally is, and you have done your normal interplanting, I tell you, I pass pack my. Especially my raised planters. I pack them very, very tightly.

Karin Velez [00:22:59]:
There is no shame in going ahead and removing some plants so that all of the plants can benefit. Okay, so if you have a bed where you've interplanted a bunch of different things, and the stuff that normally would be thriving at this point is starting to get a lot in terms of diseases. See what you can remove around the base of that plant to give it more air airflow, or consider just removing that plant. So you have to make the decision as to whether or not your cucumbers are more important to you or your kale is more important to you or whatever it is that you have planted them with. Right? That's where it's up to the gardener to decide whether or not, you know, you have to sacrifice one plant for the health or the benefit of the other. So. But spa, you know, plant spacing is Absolutely. You know, one of the factors here when it comes to a lot of these fungal diseases, and despite the rain in a lot of these areas, you know, some folks aren't getting that type of rain and you are having to water quite a bit.

Karin Velez [00:23:59]:
So a way to prevent these fungal diseases from happening is to use drip irrigation or soaker hoses to just keep that foliage dry. Even if, you know you're in an area where you're getting a ton of rain and then all of a sudden stops. Right. Okay. You're going to have to water, so make sure that you're doing it at the soil level. And then, of course, we also want to water early in the morning if we can, so that any water that splashes can dry quickly. There's always that mulch, too. Using mulch is going to help prevent that soil splash.

Karin Velez [00:24:34]:
And so that's another thing to do. And once again, we don't want to overfeed the nitrogen. That lush green flush of growth is super tasty to fungus. They love that. Aphids too, by the way. Aphids are also very attracted to over fertilized plants. So if, you know, if you've been feeding quite frequently with something that is high in nitrogen and you're starting to see a lot of fungal diseases, then we want to just go ahead and back off of that a little bit. And then once we get towards the end of the season, let's just make sure that we are cleaning up our garden beds.

Karin Velez [00:25:08]:
We're removing and destroying any diseased plant material. First of all, this also means during the season, too, if you have diseased material. I am a. I'm a proponent of the sort of chop and drop or, you know, prune and just kind of drop it onto the soil, because again, that's just plant material. It's going to break down. But we don't want to do this if the plant material is diseased, because all that's doing is just harboring that pathogen. And they can stick around not only in that plant debris, but also in the soil, just waiting for the ideal circumstances. So not just at the end of the season should we be removing this, but we should also be doing it during the season as we are pruning for that airflow or as we are removing that disease tissue to make sure that it's not sticking around.

Karin Velez [00:25:57]:
Whether you are growing in the ground or in raised beds or containers, be generous with your spacing if you have the space to do it in ground. Okay. If. If fungal diseases really are a problem, then this means as we're doing our interplanting, we really want to pay attention to that high, low, fast, slow mentality. You know, if you. If you are planting things together, make sure that the taller ones have enough room around them to be able to get that airflow, even if the shorter ones are there. And if not, we can just space them out just a little bit more. Interplanting doesn't necessarily mean crowding, okay? So be generous with the spacing, prune regularly, and stay on top of your irrigation.

Karin Velez [00:26:41]:
And doing it properly if you're not in an area that's getting a ton of rain right now. If you are gardening in a raised bed, airflow is very much a key here because you have to think you might be dealing with a little bit more humidity as those plants are kind of tucked into a container. Especially if your soil doesn't go all the way to the top, right? It's stopping a few inches shy of the top, which means the plants are sort of settled down in there. You probably need to focus a little bit more on some airflow. So just don't skimp on that, that spacing. And then if you're growing in containers that you can move around, move them right even, you know, just to give yourself some more airflow, separate those pots a little bit. Powdery mildew can. Can sneak up really quickly on, like, potted squashes or cucumbers.

Karin Velez [00:27:34]:
So make sure that you have really good drainage in your pots. If you have them on a porch or something where you can run a fan out there in the afternoon when it's just super stagnant and there's no airflow and it's just humid and ucky and gross. If a fan would feel good on you, trust me, the fan is going to feel good on your plants, too. They're going to be very happy about it. So if you can move your containers around a little bit and give them more space to increase that airflow, great. And if you need to add a fan for the health of your plants, then, hey, I'm not gonna, you know, make fun of you. I think that's a fantastic idea. What it boils down to is start early.

Karin Velez [00:28:16]:
So start applying those milk sprays or those other treatments before the fungal problems start. You want to stay ahead of the game. So if that means writing it on your calendar to say that every seven to 10 days or 14 days, you're going out there and you're repeating it, or more frequently if you need to, then do that. But just make sure that if you are having to treat very frequently that you are rotating what you're using, try to improve your airflow. So prune and stake and space your plants really well. Water smartly. So drip or soaker hoses, morning irrigation. Please make sure that you are cleaning up.

Karin Velez [00:28:54]:
Sanitize your tools, remove those diseased plants. Plants, rotate your crops around as needed. At the end of the season, treat what you can and support that plant health through the soil. Like we talked about last week. Instead of relying on, you know, those synthetic sources to to feed the plant, we want to support that plant health by feeding the soil. And we don't want to over fertilize and we absolutely want to use mulch. So if you have been dealing with powdery mildew or leaf spots or blight, don't panic, okay? You have the tools that you need. You've got the knowledge now that you need.

Karin Velez [00:29:33]:
And I'm hoping this episode will give you the confidence to kind of fight back against these fungal diseases. It is not all is not lost when you walk out there and you see these things occurring in the garden. But you need to jump on the problem immediately and take action right away in order to be able to sort of beat back these fungal diseases and keep them under control until either the weather conditions change or you get your first frost and then we're just done with the garden, right? I hope this episode will help you feel more prepared. If you know somebody who is dealing with fungal issues, then I would love for you to share this episode with them. If you have tried milk sprays or if you are having, you know, really good luck using something specific, I would love to hear how it went for you. You can shoot me a message. You can leave a comment under Spotify or in YouTube. Just send me an email reply to this week's email.

Karin Velez [00:30:26]:
I would love to hear how it's going for you. Until next time, my gardening friends. Keep on cultivating that dream garden and we'll talk again soon.