First, forget the fact that nurseries like Home Depot and Lowe's still sell tomato plants in the middle of winter. While yes, they might grow (very slowly) through the dreary days of winter and they might have even thrived in our non-winter this year, tomatoes are not cool-weather plants. They like long days and summer heat.
But with all the weather weirdness happening in Southern California right now, one has to wonder if it's safe to start tomatoes this month as opposed to early spring.
The days are bright and warm enough, and if you're starting tomatoes from seed, you can get a jump-start on the season by planting earlier and harvesting earlier. The only thing to worry about -- what with climate change and all -- is the possibility of unprecedented rain and cold in the spring, when our weather generally starts to warm up. As we've seen so far -- anything can happen here.
But if you want to take a chance, here are three tips to help ensure your tomato seedlings will survive:
#1. Start your seeds indoors or in a greenhouse, in the sunniest place possible.
Tomatoes need steady warmth for seed germination and ample sunshine for healthy growth. With our unpredictable weather this winter, it's not advisable to start your seeds outside where temperatures could dip at any moment. Sow your seeds in seed-starting trays, seed-starting pots, empty egg cartons, recycled yogurt cups, or whatever you have in the house. Nurture the seedlings until they grow their true leaves (the second set of leaves) and then divide them into separate 3-inch pots, keeping only the strongest looking seedlings. Periodically run your fingers across the seedlings each day to simulate a breeze, which helps strengthen the stems.
#2. Repot your tomato seedlings as needed.
In our climate, tomatoes are typically transplanted in the garden in March or April once the soil has warmed up and evening temps are consistently in the 60s. In the meantime, you'll want to prevent root-bound plants by repotting them one, two, or even three times until they're ready to be moved into the garden. A general rule of thumb is to repot tomato plants once they've reached three times the height of their container. Their final container should be a gallon-size pot, at which point they should be hardened off and readied for their new home.
#3. Harden off your plants before transplanting in the garden.
The process of "hardening off" a plant means acclimating it to outdoor weather to minimize transplant shock. Until this time, your tomato plant has enjoyed the safe and warm confines of your house or greenhouse. Before it goes in the ground, it needs to toughen up and get used to the breezy afternoons and chilly evenings it'll face when it's on its own. Start by placing your plants outside during the day in partial sun and then bringing them in at night. Over a period of 7 to 10 days, keep them outside longer and longer in more and more sun, until they're spending the whole day in full sun and the whole night outside. (But don't leave them out if the forecast calls for nighttime lows below 55°F.) When you see that they've survived the change in climate, you can put them in the ground (and cross your fingers for an early harvest!).