Tomato plants grown from seed

(Question)

My tomato leaves are getting too large . Can you cut them back? Not talking about suckers.

(Answer)

There are several possible reasons why your tomato leaves are growing too large and below are some suggestions.

If you have been fertilizing your plant, it would be important to look at the contents of the fertilizer.  If you add too much nitrogen-rich fertilizer to your tomato plant, the foliage begins to grow rapidly.  Nitrogen is the key element needed for the production of  chlorophyll.   You may get a  large and bushy tomato plant, but the the excess nitrogen impedes normal flower and fruiting development.   As a result, your big tomato plant may produce a small fruit yield from lack of flowering and pollination.  Nitrogen is the first number on the fertilizer label.

Once true leaves have appeared, apply a weak solution (1/4 strength) of 10:52:10 fertilizer (in this case the amount of nitrogen is low (10) compared to the middle number – the amount of phosphorus).  This should be followed by 33% strength 20:20:20 weekly or 50% strength every other week. When the plant has its second set of true leaves you can apply a 15:30:15 fertilizer at full strength

If seedlings are too leggy, reduce the temperature, especially at night; increase the light intensity; reduce overcrowding and/or pinch out the growing tips.

You can pinch the tops when they have three good, strong leaves and a fourth emerging.

You might find this Garden Guide helpful:  https://www.torontomastergardeners.ca/index.php/factsheet/growing-from-seed-a-toronto-master-gardener-guide/