Are you feeding the plants? there might be a nutrient deficiency which is causing them to turn yellow. try giving they a shot of some bloom formula fertilizer. also are you noticing any suspicious bugs?
Here is what ecrane3 usually says about yellowing leaves
"It could also be a watering problem--too much water and too little water can both cause yellowing leaves. I'd check the watering before you do anything with fertilizer since fertilizing plants that are stressed from something else can make things worse instead of better. Given where you live I suspect underwatering might be more likely, but overwatering is certainly possible as well. I'd check by sticking your finger down a couple inches into the soil and see how it feels."
In this post he was ansering to someone in California but quess it could still be underwatering.
First, I have not been feeding the plants. I purchased new potting soil (for growing veggies) this summer. I know it had food in it to begin with and I assumed that it would be enough to last for one growing season. Second, about the bugs, I found 4 hornworm caterpillars on 2 of my 5 tomato plants/pots about 2 weeks ago. These I hand-picked off. I've been looking for more since then and have not seen signs of them on any of the plants. I have spotted 2 aphids, one on my cucumber plant and one on an eggplant. These also met their doom. That was this week. I also found a stink bug on the eggplant about 2 weeks ago, also killed. Other than that, the plants have been surprisingly bug free (other than bees and a couple of ladybugs).
Other than a sprinkle yesterday, we have not had any rain for almost two weeks. It's been pretty hot! I have been going out every morning and watering the dirt in the pots (ie. not the leaves) until water flows out the bottom and collects in the plate under the pots. The dirt is moist and generally there is still some water left in the collection plate under the pots for most of the day. However, by the next morning the water will have evaporated and the soil at the top of the pots will be quite dry. If I don't water in the morning, the leaves on the plants will start to droop by mid to late day. (I wasn't able to follow my morning routine one day about two weeks ago and when I got back home, all my plants were droopy. I quickly watered them and they perked back up within an hour.)
I did some additional research on the cucumber and I think it might have some sort of powdery mildew, due to the white spots that begin on the leaves and then seem to spread. I am going to try treating it with a baking soda spray.
I found this on http://www.gardenguides.com/pests/tips/powderymildew.asp
Baking soda increases the surface pH of the leaf making it unsuitable for the growth of powdery mildew spores. Be sure to spray the undersides of leaves as well as the upper surfaces when using any of these sprays.
Here's a recipe to make your own spray:
1 teaspoon baking soda
1 quart water
A few drops of liquid soap
But the tomatoes do not have any white spots. I am convinced that they have something different; I just donít have any idea what.
I wish ecrane3 would see your post, he is so smart about this kind of thing.
Personally I tink you might be overwatering the tomato, the roots especially are probably down deep in the pot and with that much water left in the collection plate I would think the roots are quite saturated and not getting any air. They say to water only if when you push your finger in the soil it is dry about two inches down. My plants in the garden get droopy if it has been a hot day but even without watering perk right up overnight. Cucumber roots don't get that deep, at least I don't think so, but if you are over watering, the roots will stay more at the surface as they don't have to reach down for moisture.
These are just my thoughts and I could be entirely wrong. Try watering from the bottom. Put the water in the collection plate and see how much gets drawn up into the container.
Hopefully someone with more know how will have some better answers than I do.
Hope the plants decide to get their act together for you , I wish mine would too but the weather has been really weird this year, so cold all Spring and who ever heard of it being in the 40's at night in mid August. Even had frost in the northern part of the State already.
I think you're right about the powdery mildew on the cucumbers. Mine have that, as well as my squash and zucchini. I'm treating mine with neem oil sporadically, but I think you're probably on the right track to use the baking soda solution. (Or I've even seen milk suggested.)
But someone on here said that the yellowing is definitely due to a different issue - maybe something to do with overwatering or underwatering? I'm not sure. Maybe ask in the tomato forum?
Interesting what you say about air, surrey. I don't think that overwatering is an issue with my cucumbers and squash at the moment, but maybe I need to get the hoe out and get some air down in the soil.
sorry for the threadjack, teachn. Just thinking out loud . . .
Potting mix might have enough "food" in it for flowers, but not for a whole season of growing tomatoes. It's time to feed your plants. TomatoTone is 4-7-10. GardenTone is 4-6-6. Vigoro is 12-5-10. I've heard of success with all 3.
Someone over on the perennial forum mentioned you folks were looking for me so I figured I'd pop in over here! Thanks for the vote of confidence on my knowledge...but unfortunately I don't grow veggies (which is why you don't see me over here much) so I'm not sure I can add much more beyond what's already been said here.
I would definitely check on your watering, that's always a prime suspect for any sort of plant that's having trouble. Next time before you water, try sticking your finger down a couple inches into the pot and see how it feels--the surface dries out very quickly especially if it's sunny, but underneath a couple inches it could still be very wet. Being too wet can cause wilting, and also even if a plant has plenty of water, it can wilt on a hot day while the sun's on it because it can't take up water fast enough (when this is the case, you'll usually see it perk back up after the sun goes down) If they're wilting regularly and they do have plenty of water, you might consider moving them somewhere that they get just a pinch less sun during the hottest part of the day.
I would also check for sucking insects--anytime I have a plant that I know is getting enough water but it seems to be wilting more than normal, there's generally either been a gopher that's chewed the roots up (very unlikely here since it's in a container!), or there's aphids or scale or mealy bugs or spider mites on the plant somewhere.
And of course needing fertilizer is also a possibility--veggies need to be fertilized regularly for best results, and those potting mixes that come with fertilizer already in them really don't have much fertilizer at all in them, so for plants that are heavier feeders you definitely need to add additional fertilizer. But if you discover that you haven't been watering properly or that there are insects around, I would hold off on the fertilizer since fertilizing a plant that's under stress from some other problem can make things worse.
Thank you guys so much. I'm checking my plants and trying out what you have suggested. I'll post again before the end of the week with an update.
And thank you ecrane3 for visiting a forum you don't normally visit. I believe that I can 100% assure you that my troubles are not caused by gophers. : ) But I will keep that in mind for the future. Next year I hope to plant a big garden in the ground. However, gophers may be the least of my worries then. I'll have to battle the rabbits and deer (and turkeys?).
This update post is a little late. I've been very busy. My tomato plants haven't been getting any better. They are not over watered. I have been watering from the bottom (ie. putting water in the dish under the plant and allowing the soil and roots to draw it up) recently. When I check the soil in the morning, it is dry about two inches down. They have been fertilized. It doesn't seem to be helping. And I've continued to check for bugs. I don't see any. There are no spider mites. On the positive side, they are determinite tomatoes and all the tomatoes on the plants have started to turn ripe. Last week I was able to pick my first tomatoes. More and more continue to turn yellow, then orange, and red. I'll be picking more today. So, all in all, I'm no longer that concerned about the plants. They are dying. I don't know why. But. . . I think they'll live long enough for me to harvest all my tomatoes. Next year, I'll be planting in the ground. And next year I'm going to try heirloom tomatoes.
As of this post your tomatoes are long gone; however for next time you try this method I have some recommendations.
First you were not overwatering at all, you are under watering. I would recommend watering in the evening also.
What size were your pots? This will make a huge difference in how the plant responds to under watering. The smallest size I would recommend would be a 5 gallon pot. This will allow for more moisture content to make it through the hot day. If you miss one day in the hot time of year, it will cause problems just like you experienced.
Secondly potted plants MUST have extra nutrients as there is very little area for the roots to stretch out and feed. I would agree with the earlier post on recommending Tomato Tone and Plant Tone. Espoma has wonderful products that will not burn your plants. Here us a link to a page that has both, http://www.gardenharvestsupply.com/category/espoma-s-plant-foods
Wow, thank you. This coming year I plan to plant most of my tomatoes in the ground, but I think I'll still have a few in pots. I can't remember exactly what size my pots are, but they are big. I think they are either 10 or 12 gallon pots.
So. . . you don't think they were diseased, just underwatered? And perhaps needed more fertilizer?
Last year, I was having issues with my beans (in hanging pots) turning yellow. I watered every day that they did not get rain, and the drainage was good, so I could not figure out why they were unhappy. After reading the post, I put a wick in the pots, to help move the water along. It worked. The beans started leafing out happily, with green leaves and they produced some very tasty beans. It took a while for my brain to realize that the airflow that worms usually give me was not available for the containers, and so they needed something else to help.
Additionally, as an experiment, I took a chopstick and poked a bunch of holes in the soil between the plants. I also used a VERY small amount of peroxide in a watering on one set of plants. I'm talking about a tablespoon of peroxide in two gallons of water. However, the plants thrived.
I hope this helps for your next round of vegetables.
Nope. I mixed some potting soil and peat moss, then added some time release fertilizer to the mix. I thought that the mix would be enough to give a nice light growing medium. I was right, for the first part, but it eventually settled down. I'll have to try other stuff this spring.
You're welcome. The article about water movement was a major eye-opener for me. This time, when I put the plants in the containers, I'm putting a wick in to start with. That way, I won't have to get creative halfway through.