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Rain is usually a welcome sight here in San Antonio. We get to save on our water bills, the whole world around us is a vivid green hue, and we get to enjoy the cooler temperatures that come with rainfall. We think that besides having to reschedule a few baseball and softball games, or moving a picnic indoors, the rain is not much of an inconvenience. That is until we pop back outside after the rainfall has subsided and happily go to inspect our tomato plants, which have sky-rocketed in height, and find a grisly sight. The bottom leaves have decided to forgo a brilliant green hue and opted for a gnarled, brownish-yellow, spotted attire instead. While we’ve been cozy inside, happily thanking the rain for doing our watering for us, it has been happily splashing up soil dwelling fungi up on the bottom of your tomato plants leaves. Holy Leaf Blight, Batman! You do your best James Cagney impression while you shake your fists at the rain, “You dirty, double-crossing rat!” Although the rain definitely has had a hand in your fungus issue, it can’t be blamed entirely for the problem. Let’s take a look and see what could have been done before, and what can be done now, if anything, to save your precious tomato plant.

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(Even the Happy Gardener has fallen prey to Early Blight. You can see how the leaves are showing telltale signs.)

Brown, elongated, sunken lesions, dark-brown spots with round rings, and leathery, sunken spots; sounds like a case for the Mayo clinic doesn’t it? It’s not, but to gardeners all over, it can feel like a death sentence, and quite honestly, sometimes it is. What we are seeing a lot of is Early Blight, which is a foliar disease, very commonly found on tomato plants this time of the year when conditions are favorable to it. Alternating periods of wet and dry weather with temperatures ranging from 65-85 degrees provides the perfect breeding ground for Early Blight to rear up its ugly head and strike before you realize what is happening. This disease starts at the lowest leaves of the plant, making its way up the stem, quickly gobbling every leaf in sight. The plant will end up partially defoliated or possibly, gasp, naked! This will weaken the plant and reduce the size and the quality of fruit. This disease can affect your tomato plant at any stage of growth.

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(This looks like a lost cause and might be best to pull this one up and follow the prevention tips next time.)

If you think you see the first inklings of it (the yellowish-brown discoloration on the leaves at the base of the plant), clip off a few leaves, stick them in a ziploc bag, and run, don’t walk, to Rainbow Gardens to allow us to verify the problem. It is here that we can identify the issue firsthand and get you the fungicide product that will work best. I stress that you should bring us your sample at the first sign of this disease because if you opt to remedy this problem by, say, ignoring it (never a good option) it will creep not so slowly up the entire plant and there will be nothing you can do to save it at that point. Then you will bring your naked tomato plant into us, hoping for a miracle, and we will tell you to give your tomato plant a proper burial. Sooooooo, if you think you have the disease, bring it in, and we will steer you towards the best fungicide according to your gardening preferences. If prefer organic gardening, you will be looking for a fungicide that has copper for its main ingredient such as Liquid Copper Fungicide from Bonide.

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(An organic option to fight Early Blight in its early stages.)

If organic is not a priority, you can use Daconil Fungicide. You will want to remove as many of the damaged leaves as possible, throwing them into a bag to be disposed of immediately, and then treat with your chosen fungicide. The key here will be to remember to follow up with subsequent applications according to the label on your fungicide. Usually you will need to repeat treatment every 7-10 days, especially during consistent rainfall periods, to get the disease under control.  If the disease has taken its toll and spread all the way up the plant, it’s possible you might have to chalk it up to a learning lesson and throw in the towel as you also throw away the tomato plant. Carefully pull up the infected soul and dispose of it immediately. It does not get a rebirth in the compost pile unless you are keen on spreading disease with wild abandon. Nope, I didn’t think you were. The death of a tomato plant has probably been traumatic enough.

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(A synthetic option for fighting Early Blight.)

The best thing to arm you with is the knowledge of how to avoid this disease in the first place. Before you know, it will be mid July and time to plant tomatoes for your fall crop, so let’s figure out how to prevent this carnage from happening all over again. Did you know that many tomato diseases remain in soils for years? Chances for your tomato plants to be infected with disease are high if you had tomatoes last year that suffered disease, and you planted new plants in the same area this year. Your first line of defense it to avoid planting tomatoes in the same spot in the garden. It is not always known, but always advised to rotate your crops each year and to limit the risk of contamination from previous soil-dwelling disease. Also, before planting, you should take some time to think about your soil. Soils rich in compost and beneficial microbes greatly reduce the risk of soil dwelling disease. Mix in some Happy Frog Jump Start fertilizer with active soil microbes, or Espoma’s Bio-tone Starter plant food plus mycorrhizae, and give your soil a fighting chance against those nasty fungi.

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(Yummy organic fertilizer for your plants and chock full of active soil microbes to help prevent soil disease.)

Along with planting your tomatoes in a different area each year, you also need to think about space. With the whole square foot gardening craze, we’ve all gotten excited about how, with such little space, we can grow more vegetables than we ever dreamed of. Not so fast, you still need to take in account how big your veggies are supposed to get at mature size. Tomato plants, especially indeterminate varieties, can grow to monster proportions. If you crowd your plants you don’t give them enough room for adequate air circulation. Ever been in a hot, stuffy, crowded elevator? That’s pretty much what it feels like for your tomato plants when planted too close together. They really should be planted at least 3 feet apart for optimal growth and vigor. Crowding = no air circulation = opportunity for disease. Also, go ahead and pick out disease-resistant varieties when you are choosing which tomato plants to buy. Here’s a list of different tomato varieties, many of which Rainbow Gardens can find at the right seasonable time.

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(Tomato plants NOT given enough room to breathe. There’s four in that row believe it or not!)

Now that you’ve taken care of your soil, you’ve chosen disease-resistant varieties, you’ve chosen a new area to plant in, and you’ve spaced out your plants, the next step is to protect your plants from the splashing of soil that comes from rains, and overhead irrigation. First off you need to apply a layer of mulch around the base of your plants. Mulching around the bottom of the plant can greatly reduce the disease from the soil being splashed up onto the lower leaves of your tomato plant (one of the favorite ways the disease likes to spread). This is kind of like putting Captain America’s shield between the evil fungus and your susceptible victim. You’ll provide a barrier for when the rains come and even for when you are watering with a hose, garden pitcher, or sprinkler. Next…stop watering with that sprinkler! It is much more efficient to water around the roots where the tomato plant wants to receive the water. There is no benefit to watering the tops of your plants, you’re not cooling them off during a hot summer day, you are just increasing their chances for leaf scald, and the soil to be splashed about the plant. A drip irrigation system is ideal, and now is a great time to install one while the weather is cool enough to enjoy working outside.

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(Mulch to prevent soil being splattered up on leaves.)

Now you should put yourself on a maintenance schedule. Feed your plants regularly, visit your plants regularly, and pull the fruit from your plants regularly. Tomato plants that are poorly fertilized and loaded with fruit tend to be the most susceptible to disease. Give them a dose of that microbe infused plant food (Happy Frog, Espoma). Don’t let the tomatoes dwell on the vine for long periods of time, they should plucked and chopped up for salsa or some other recipe. You didn’t grow the plant for the squirrels, did you? Don’t just watch from the window and think your tomato plant is doing great because you’ve noticed it getting taller. Go out and visit it, paying close attention to the leaves towards the bottom. And finally, prevention is your BFF. If you notice the weather conditions turning wet, dry, wet, dry with temps around 65-85 degrees, put your fungicide in your holster, start whistling the tune from “The Good, The Bad, and The Ugly”, and stride out to take care of business. After all, this is your garden, your tomato, and if the weather tries to throw you for a loop, “them’s fighting words!”

The Happy Gardener says, “Good luck, and long live the tomato (and its leaves)!

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-Lisa Mulroy

 

 

Choose disease-resistant varieties

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—Once you’ve got it.