Yellow Leaves on My Tomato Seedlings

by Tom Heins
(Orange, Conn.)

My tomato plants have been grown from seeds and are about 4 inches high. They are under grow lights for 4 weeks and are in 4 inch peat pots.

I spritz them every day and now the first leaves are starting to turn yellow.

It still a little chilly here so should I start planting outside?

I started hardening them for the past 3 days, for 3 hours a day.

I live in Connecticut near the shore; temperatures are about 50 - 55 degrees F. days and nights 40-45. Too early?

And why the yellow leaves? They are with all my other plants in the greenhouse; peppers, squash, cucumbers, and melons.

I am a newby gardener with a brand new raised bed; 12 x 12 x 8.

Will be be planting soon. Need help. Been to library and have read every book on gardening as well as this website.

Thanks in advance.


ANSWER:

Usually yellow leaves on tomato seedlings means they are being over-watered. Tomatoes are sensitive to too much water. Just be sure that the soil in the pots completely dries between watering. Too much watering also depletes the soil of nutrients, which can cause the yellow leaves.

Your tomatoes will likely recover from this as soon as you cut back on the water.

It is still too chilly to plant them outside. The tomato plants will not grow very fast until the daytime temperature reaches 65-85 degrees F, or the soil temperature reaches 55-60 degrees F.

Until then, they will grow faster in the green house, and give you larger plants when the time is right for planting outdoors.

Best wishes with your new garden; send pictures later if you can!