Are there any gardening experts here?
Hello. I am quite good with tomato :) Having the photos would help to get an overall feel of the problem.Can you also give me an overview of your soil? As in what kind of soil it is, what kind of soil amendment did you use and any fertilizer that you used.Also, are they outdoor or in a greenhouse?
Great, here's the scoop: 5'X10' raised garden bed (about 9" high) filled with E.B. Stone organics Planting Compost. E.B. Stone "Sure Start" mixed in (whole box). About a tablespoon of E.B. Stone "Vegetable and Tomato Food" at the bottom of the root ball hole. The transplants were about 6" high when they went into the garden about a month ago. Usually my plants are much darker green in color.
It does not seem to be a disease but more a mineral deficiency. As you mention raised bed and they seem outdoor, perhaps too much watering or rain caused iron to leach out of the soil (compost don't have much iron). Iron is also badly absorbed if no calcium is present. Egg shell powder and rusty nail can do the trick.It might also be a lack of Nitrogen. Nitrogen help the cellular division and to get larger leaves. This can happen if the compost is not decomposed enough. The decomposing agents eat all the Nitrogen and few is left for the tomatoes. Those organisms eventually die and give it all back to the area but the plants are retarded.Magnesium deficiency may also be involved but as they just don't look super and not bad it's hard to know at this point.As a hint to get them to start strong, plant them at 3/4 (including the base leaves). The stem will develop extra root along it and it will adapt faster to the soil. Also if you can use sheep decomposed manure you pretty much remove any risk of mineral deficiency.If there was too much sun and dry air for long period it can also stunt the plant but as it seem to have produced OK tomato so far, it might not be the case.
I was concerned about a nitrogen surplus or deficiency as my research points to either one. (further clouding the issue). I'm in SoCal, so we don't have too much rain, but I've got them on a timer, delivering water three times per week via soaker hose for about 10 min per session. Shouldn't be too much? They receive full sun 8 hr per day. Can you point to something more concrete that I can do? They are setting decent size fruit, though there doesn't appear to be as much as in previous years. Can you elaborate on the rusty nail technique and where to get egg shell poweder. I was thinking it's possible if it's a nitrogen deficiency it may work it's way out in the next month...?
Too much Nitrogen would cause too much growth of bad quality (not able to stand up) and if far too much then root burn occur and the plant would look in bad shape. Added Nitrogen show fast when the plant are young but less when they are established. Even if it's tempting to use fast release granule, it's better to use slow release to prevent the burn risk.Soaker and 10 minute seem too much. Especially that you have compost to retain humidity. Lower this and check by digging if the soil is humid enough before the watering take place.For the nail, you just insert a rusty nail in the soil near the stem. And for the egg shell, you pound them into a powder unto a mortar (or a bowl) and put 2 or 3 at each plant. Water will eventually dissolve it in some weeks. You may only see change in new leaves as the size of the current one is now set.When i have problem like that i always keep a plant that i don't treat to see how much the correction improved the plant or if there is no change at all.Another possibility i forgot to talk about is if you use seed from last harvest. Eventually you need to mix new blood of the next generation eventually become weaker and lack vigor from too much interbreeding.