How can I prevent common diseases?

[Oboegirl]

It is now time to start planning and seeds for our vegetable and herb garden and I'm struggling to get the motivation. For the past few years it seems like a loosing battle with 2 diseases: blight on my tomato plants and powdery mold on my zucchini and squash. We have only one spot in our yard that gets enough light for growing so I have to put my plants where they are. Each year I dig my holes and add bone meal and organic fertilizer and by the end of the summer we battle with trying to get the tomatoes to ripen before the plant dies. We spray with Serenade weekly once the plant shows signs of blight and powder mold. Our zucchini, cucumber and yellow squash yield is tiny compared to what it should be. It's frustrating. Is there anything I can do to stop these diseases before we plant? Honestly, I'm thinking about just giving up and buying stuff from the farmer's market. I love growing our own food but the frustration is real. Any suggestions???

 

[Chuck]

First of all where do you live and is the blight the early or late variety. Blight of either type is difficult to control but can be done. I used to have early blight every year but have learned through trial and error how to control it long enough for a complete harvest. I don't nor have I ever had late blight. I don't think it grows here. As far a mildew on your cucs and squash basic gardening techniques will reduce much of the problem and by this I mean zero overhead watering, application of whole ground cornmeal and a spray regimine of a good fungicide like Serenade. Mildew is caused by long term high humidity and excess surface soil moisture. Application of whole ground cornmeal will help greatly as the corn meal is the best growing medium for tricoderma fungi which destroys harmful fungi. Let your plants of all types dry out between waterings. Watering frequently hurts more than helps plants. The secret to watering is to water slowly and deeply. I live in South Texas where it is very hot and very dry with very high humidity and I water about every 7 - 10 days if it doesn't rain which in the summer it rarely does. Please update your profile to let us all know where you live so we will all have a more complete knowledge of how to help you in the future.

 

[DirtMechanic]

I had your exact problem. I started fixing it from the ground up.

Make sure your compost and other additives are sterile and weed free. Crap in, Crap out. Also do what @Chuck says.


I use Humagro Promax as a soil sterilizer. Sounds weird, but seed starter soil is sterile too and for good reason. You did not say what blight you have, but early blight is my guess by your description. Scroll down the highlighted link page and read what the HP will stop in the garden. One other problem I identified was knotted roots. Nematodes! I spray the soil in the early spring and till it in. I wait 2 weeks and do it again. 2 weeks later I do it again and plant. The soil is a staging ground for many insects and fungi. Hit them hard in the spores and you open a growth window. You will not win in the long run but you will bring in the crop with minimal plant damage so that is the goal, and its over a few months not all year. Simply reset if you run a winter garden.

I use Humagro Promax as a major part of my spray routine after tilling. It is a thyme oil-humic combo. If you have tomato outside you will spray at least every 3 weeks so get a sprayer. I use it liberally on the whole garden. It even helps keep the bugs off my cucumber, and because they bring bacterial wilt, I am able to bring in buckets full.

The HP has an oily base and makes a coating. Coatings, oils, silicones, are all useful as a protective layer from bugs and fungi. They do not last so spraying every 2 weeks is realistic. Tomato has a matte finish leaf with lots of surface area to catch and hold spores. I wish they were waxy like a magnolia.

The HP has a strong but not altogether unpleasant smell. Neem oil probably should be added now and then. Of course try to avoid flowers by spraying hard just prior to bloom so you can ease back during flower for 2 or 3 weeks.

There are still fungi for which there are no cures. Usually wet conditions hurt so the better the drainage the less fight you have to put up. If that means raised bed or hill row then so be it. @Chuck is spot on about using fungi to fight fungi. Do it. Also there are some other beneficials like mycostop and actinovate that are literally the same group of bacteria that pharmacists make a lot of organic antibiotics from called Streptomyces.

One product will never do it all, but if it saves some of the back breaking labor so be it. Thats why I like to spray, I can often combine several things into one effort.

 

[DirtMechanic]

One thing I forgot to mention was a surfacant. Some are made from coconut oil, and are good for helping stick the treatment to the plant better. Polysorbate 20 from this company comes with a description that might help.

 

[Oboegirl]

First of all where do you live and is the blight the early or late variety. Blight of either type is difficult to control but can be done. I used to have early blight every year but have learned through trial and error how to control it long enough for a complete harvest. I don't nor have I ever had late blight. I don't think it grows here. As far a mildew on your cucs and squash basic gardening techniques will reduce much of the problem and by this I mean zero overhead watering, application of whole ground cornmeal and a spray regimine of a good fungicide like Serenade. Mildew is caused by long term high humidity and excess surface soil moisture. Application of whole ground cornmeal will help greatly as the corn meal is the best growing medium for tricoderma fungi which destroys harmful fungi. Let your plants of all types dry out between waterings. Watering frequently hurts more than helps plants. The secret to watering is to water slowly and deeply. I live in South Texas where it is very hot and very dry with very high humidity and I water about every 7 - 10 days if it doesn't rain which in the summer it rarely does. Please update your profile to let us all know where you live so we will all have a more complete knowledge of how to help you in the future.

Thank you! We are in Wisconsin. We get early blight. We do drip irrigation but still get the white powder. I've not tried the cornmeal idea and we will absolutely do that this year, thanks for the suggestion! I'll get to work on my profile now, thank you!

 

[Chuck]

Thank you! We are in Wisconsin. We get early blight. We do drip irrigation but still get the white powder. I've not tried the cornmeal idea and we will absolutely do that this year, thanks for the suggestion! I'll get to work on my profile now, thank you!

Just remember to water deeply. The soil stays moist a lot longer at root level than you would guess. Let the top stay dry. Your plants will tell you when they need water by wilting in the AM hours. When they wilt it is time to water and not a drop before then.