Is it possible to overwater potted tomatoes growing in a dry climate? What are the signs that they are overwatered?
Are these tomato plants over-watered? Does it have blight? Is something else wrong, too?
This one has a "raisin"!
Watering plants everyday is not good ONLY when the plant does not need the water. My tomatoes are always in pots in our climate so that I can move them in and out when the weather changes, mostly every dang night. Being in pots in potting soil always, they dry out quicker but I still never water every day. When they are starts in small pots, yes they are watered every day. But they are slowly trained to be in larger pots. Small plants in large pots just will never do well.
For potted tomatoes it is easy. I soak them when I water and do not water again until the pot is light. Which is every other day, sometimes every day until they are ready for 5 and 10 gallon pots that hold onto water longer. In the ground it depends on what soil you have. Are they in raised beds with decent drainage or are they in heavy clay planted in the flat ground?
Have your tomatoes ever wilted if you did not water every day? How deeply do you water when you water? Is this in your garden or on a patio in a pot? It is never a good idea to water on some 'schedule' us humans make. It is hard on a plant to allow it to begin to wilt but sometimes that is what it takes to see how long your soil holds onto water and to allow your plants to work at growing deep roots. The more you water the less those roots will work at getting at the moisture down deep. Shallow watering, shallow roots and a plant that you forget to water will be very unhappy.
We need to know where you live, what kind of soil you have to deal with, did you plant in your garden without making a raised bed, or did you make a raised bed (doesn't need any structural elements to make a raised bed), do you water overhead or do you use drip irrigation?
I would water your plants normally then take a spade and dig into the plant bed to see how deep your watering got into the soil profile. If it is only an inch or two then double or triple that time to make the soil wet, down at least 4 inches. Allow the soil to dry at least 1 inch deep before watering deeply again. Watch for wilting. Make note of how long you watered, how deep the water got into the soil and if you see any wilting make note of that length of time.
Prune the lower leaves off of the stem. Do not water over head. When young no problem but later water splashing up off the soil onto the leaves could easily infect your tomatoes with blight. A fungus that infects with just one spore splashed up in water...and that plant is done. This part is all about tomatoes in your garden. When your plants get too dense feel free to prune off vegetative branches/leaves without flowers to enable air to move through your tomato plant. Just enough to thin the inside of your plants. Movement of air helps to deter other fungus such as powdery mildew which later on becomes inevitable.
Water only the soil without splashing. Drip irrigation or hoses with holes works well. Hand watering is worthless. Soaking the soil then allowing it to dry before watering again helps to train deep roots and less watering and a healthier less apt to get fungus plant.
Have you grown tomatoes before? Is this in the garden or in pots...? Please send pictures and more information. Nothing is irrelevant. If in pots, did you use potting soil or did you use garden soil...lots of questions need answers so that we are better able to personalize your answer. What mulch? What kind of fertilizer? Anything.
Check out the other question/answers on tomatoes particularly on blight. Might help to engender more questions. Tomatoes are enormously rewarding when done correctly. To lose plants to blight or p. mildew or animals is a major bummer.
Ugh. This looks like early tomato blight to me. Almost certainly. 99% sure. I would get rid of these plants, tomatoes and the soil. I'd say bag the debris but to worry about spreading this disease is fairly moot. You will always have the spores of this fungus on your site, indoors and outdoors. Where you went wrong was using unsterilized mulch. Just one spore and that disease is there with you forever.
Not to worry. I've gotten this disease in virgin garden soil that had never known a tomato or any vegetable. Truly a bummer but if you've been getting tomatoes for 2 years without fertilizer you are due to start over again with fresh plants, fresh potting soil, do not use anything else in that soil. Period. Get a little bottle of Osmocote fertilizer. It is extended release and lasts for a good 3 to 4 months. Forget mulch or any other additives.
I always grow tomatoes in pots in potting soil now and always start anew every season. If I were living where tomatoes could be the perennial they are I would still get rid of my tomato plants and start anew every 4 or 5 months. Blight is such a common yet completely devastating disease and those spores can just blow in. I assume you pots are on a patio? One spore could be pooped out by a bird or blown onto your plants while the leaves are wet and you will lose your plants and all fruit produced.
Tomatoes do not do well in doors. The other option is to make a little green house for your tomatoes with plastic and use only sterilized potting soil. When it isn't raining you can keep the plastic cover off. Put it back over your plants at night. Did you say where you live? Where are your pots? Bummer. I learned about blight the hard way. My first major garden had perfect soil, never anything grown in it except weeds and grass. Yet, my 3 , 25' rows of gorgeous 4' high plants laden with beautiful tomatoes got blight. I noticed the signs and in 3 days every single one of my plants turned black and dead. I tried to harvest the tomatoes and every single tomato eventually turned black. This was 'late' blight but the same principles hold true for early blight. Once your plants get infected it is a done deal. That is why I always plant my tomato crop in pots and work my way up to 5 and 10 gallon pots always with fresh, sterilized potting soil. A little fertilizer, the ability to take them inside to my grow room and soon to have a fully enclosed self sufficient greenhouse, haven't had or expect this to happen again. Keep your fertilizer where the nitrogen has the lowest percentage number in relation to phosphorus and potassium if you want tomatoes instead of lots of leaves. You have to 'add' fertilizers if you use mulch, fish fertilizers, compost teas, bone meals etc. Mulch or compost or these other additives are for garden soil use and should not be considered fertilizer. They are more important in other ways to your crops but still need to be accounted for in your 'fertilizer' program because just a little too much fertilizer will kill plants and a little too much nitrogen in proportion to the other chemicals necessary for photosynthesis will promote vegetative growth not reproductive growth. Great for lettuce, rhubarb, kale, spinach and other leaf crops. But no for tomatoes. Some of these additives for garden soil are to promote soil organism life and to add bacteria and beneficial fungi, not for adding chemicals that your plants have to have to do the work of photosynthesis where plants actually make their own food.
Water only when the soil has dried out an inch deep. Did you put any gravel or rock below the potting soil and above the drainage hole in your pots? NO? Super duper!! Do not put anything in your pots other than potting soil. Otherwise you compromise drainage in a very big way. No tiles no rock meant to hold the soil inside the pot. That is never a big deal. If you worry about that then a piece of that shade cloth or panty hose over the hole is ok. Not necessary. Fertilizer is critical. That good ole Osmocote is my recommendation. It is by Scott's and the only product they make I will use much less recommend. It is extended release. Follow the directions and you can forget worrying about any other fertilizer. Fertilizer is NOT food. It is the chemicals necessary for the plant to do photosynthesis in order to make its own food and flowers and seed and fruit that you want to eat. I hope this helps. Bleach those pots well before adding potting soil and your new tomato plants.
Respectfully, after growing hydroponic tomatoes for several years now (tomatoes grown with roots in, and some under water) , a yes or no answer is not suitable to address the question. The deepest roots are fine to be submerged completely under water for the entire life of the plant. The upper buttress roots, close to where the roots begin to appear on the stalk need to “breathe” oxygen. They can be wet but not submerged for several days or the plant will drown. Growing tomatoes hydroponically may be a great solution to growing tomatoes in a dry and hot climate. I use 5 gallon buckets, and my plants grow to about 8 feet tall. There are several ways to do this and in my opinion it is an easier and more efficient way of growing tomatoes than in soil, however, I do grow some in the soil. One thing to be careful of (that I haven’t seen addressed anywhere) If growing in full sun make sure to find a way to keep the water buckets (for hydroponic plants) from becoming too hot. That can also kill the roots. I actually grow mine in part shade and that works here. I also grow cucumbers hydroponically in an old Coleman cooler. That keeps the water from becoming too hot, even in direct sun.
Adding a couple of photos to supplement my post. As I said before, I believe hydroponic growing would be an excellent way to grow tomatoes in hot, dry conditions. Takes much of the guess work out of it. So a more precise response to the question would be- Tomatoes cannot be over-watered, however they can be drowned if their “breathing” roots are submerged for more than a day or two.