Time to start summertime tomatoes

Jan. 12, 2013 @ 11:19 AM

It is the second week of January.  I think that it is time to start talking about summertime tomatoes. 

Most of the farmers who raise tomatoes to sell at the Durham Farmers’ Market start their plants from seed and the summer tomatoes usually start their journey to the market in mid-January.  

Tomatoes have a relatively long lifespan -- growing a tomato plant from a seed takes about 130 days, or 4.5 months.  To compare it to other summer crops, green beans take about 55 days from seed to maturity and summer squash takes about 50.

The tomatoes that will be showing up at the Market in June are being started in greenhouses across the Piedmont right now.

Tomatoes are thought to have originated in Central or South America so, to start them from seed, they need very specific warm conditions.  Local farmers start their tomato seeds in small, flat trays in greenhouses heated to a constant temperature of 75 to 80 degrees.  For the seeds to germinate, the soil temperature must remain constantly warm and moist. 

Light is also critical at this stage.  Because the day length is short and the angle of the sun is low, farmers often use grow lights to make sure their seedlings get adequate sunlight on even the cloudy and dreary winter days. 

The tomato seedlings will stay in the greenhouse for 6-8 weeks.  They are ready to be planted when they have several true leaves and a nice strong stem.  Farmers time it so that these conditions coincide with weather conditions that are good for tomatoes, which include warm soil temperatures, longer days and no risk of frost. 

Six to 8 weeks from now is early March, which is a few weeks before the last predicted frost date.  So, the first seedlings will mainly be planted in high tunnels, which are unheated greenhouses. These high tunnels keep the nighttime soil and air temperatures slightly higher than the temperatures outside.  With high tunnels, farmers are able to have tomatoes ready a few weeks earlier than they would be if they were only planting them outside.

Through the rest of January and February, farmers will start several rounds of tomato seedlings (and other crops as well).  Staggering plantings means that they can have a long growing season; when the first planting is done bearing tomatoes, the next planting is just starting to bear.  The first round of summertime tomatoes will be available mid-June.

As we are enjoying the plentiful greens, carrots and hot-house tomatoes of the wintertime, farmers are plotting out their next crops and getting everything ready for the next season’s market offerings.

Erin Kauffman is market manager for the Durham Farmers' Market