What Is Wrong With My Plants?

[sparkingwires]

The beginning of the year I decided to try my hand at making my own seed starting mix with sphagnum moss and perlite since there seemed to be a shortage of seed starting mix near me.

Everything has been great, however I noticed that some of the leaves of my plants are starting to turn more yellow or splotchy as they mature. I have been applying Jacks 20-20-20 (1/4 tsp per gallon) to the seed trays about once a week. I am wondering if I am applying too much, not enough, or if the soil is missing some trace nutrients.

Note that these are all in a greenhouse with the temperature averaging between 50 - 80F.

Here are some photos:

Beefsteak Tomato

Yellow Squash

Cuke

Basil

Mint

 

[Oliver Buckle]

I reckon that mix contains practically no nutrients, which is okay for sprouting seed, the seeds themselves contain what is needed to get going. Your plants though look like they are well advanced, I usually start potting plants on separately as soon as they have real leaves, I don't want the roots to get too mixed up and damage when I separate them. I drop them onto the potting tray so the soil breaks up a bit and tease them out holding the leaves. Keep your hands off the roots and stem if you can, they only have one stem and roots are permanent, but they make new leaves all the time, and pot them on into something like two parts compost, one part top soil and one part well rotted manure into pots with plenty of room. Plants like stability, and the bigger the pot the less fluctuation in temperature and water content.