Mine are in 10 inch pots stood in watering trays trays, I was leaving water in the trays as I was told tomatos preferred to be watered from underneath, I did use cheap compost which may have been the problem... Next year I'll cough up for some better stuff...
I think the compost you use makes a huge difference. I grow my tomatoes directly in the soil of my polytunnel, in ground very well manured with FYM, comfrey leaves and seaweed meal, plus a tagetes plant for each one to keep the pests off.
However, I start them off indoors in pots, and I've found what I use in those pots is vital to the crop. One year the compost was contaminated with weedkiller from source, even though it was supposed to be good quality.
I think the organic composts, if you get a good make, hold their nutrients for longer, but a point comes with both when the growing medium has no feed at all left in it. Also, if you use something like a peat based compost and it dries out, it's very difficult to re-wet (you can add a few drops of washing up liquid to the water, which helps). I pot on my young tomatoes frequently, both to stop them getting pot bound, and to keep up the nutrients.
For good growth, tomatoes need nitrogen rich feed before the flower buds appear, then high potassium (comfrey, tomato feed) thereafter, and the flowers sprayed with water.
They do need loads of water, but not so much that they can't suck it all up within a couple of hours. If the roots are standing in water, they will have no oxygen, then rot. If your roots are poor, then bury the plants a few inches deeper than usual in the growing medium (easier in soil) and they will grow extra roots from the stem.
For watering when mine are in pots, I pour feed on from the top, but plain water from the bottom. You can also see if they are wet or dry by lifting the pots and testing for weight - won't work obviously for growbags, unless you have several arms.
Bionic - you
must have comfrey; can't garden without it.
Topic: Why are my tomato leaves going yellow? (Read 9154 times)
