Potting Up Tomato Seedlings

My tomato seedlings have grown all the way up to the grow lights, so it's time to pot them up.

I started by making a soil mixture.  I used to buy potting soil until I realized that it wasn't really necessary. Now I mix some coir (coconut fiber that has great moisture retaining properties), peat moss, finished compost, and some garden soil. I mix it all in a large storage tub.

I often use old plastic pots, but I don't have many this year. Instead, I used 9 ounce cups. The 9 ounce cups are a good size for me because they fit well into the trays that I put the potted up seedlings in. They will last a couple of years, so I can reuse them before eventually recycling them. They need a drainage hole, so I use a cheap soldering iron to melt a hole in the bottoms of the cups.

I had terrific germination. I usually place two seeds in each peat pellet in case one doesn't germinate. This year, almost all pellets had two seedlings and a few had three. There must have been some tomato seeds that stuck together.

I take off the netting on the pellets and tease the seedlings apart, trying to retain as many roots as I can for each seedling.  Then I remove the first set of leaves at the bottom of each stem and bury the seedlings deep in the bottom of the cups. Roots will sprout along the buried stems and create a strong root system for each plant.

Once the tomatoes are potted up, I start hardening them off by placing them outside when the temperature is above 50 degrees. I start with 4 hours and gradually increase the time that they are outside until they are able to stay out all night. On the days and nights that forecast low temperatures near 50 degrees, I bring the plants inside. Temperatures any cooler will delay the seedling growth. I may plant them in early May if warm weather is forecasted or after May 10th which is our frost free date.

Putting the seedlings out early gives me more room under my grow lights to start an early round of cucumbers, melons, and beans. I give them a head start and transplant them out after the frost free date in Indianapolis, May 10.