Start cool-season vegetables now
March is a great time to start growing early cool-season vegetables. This group includes leafy ones like spinach, lettuce, and arugula; greens like mustard, bok choy, collards, and kale; bulbs such as onions and leeks; and legumes such as peas. Wait until April to plant radishes and root vegetables like beets and carrots. Warm-season crops should not be planted until after mid-May, when danger of frost has past.
You can get starts from nurseries, or plant seeds directly in the ground. Because it’s still cold at night, a cold frame, low tunnel, or hoop housewill help protect your tender seedlings. Also, put some winter-weight row cover over seedlings at night to give them an additional 4–6° F of protection. Even if you don’t have a cold frame or hoop house, you can put row cover on a raised bed over the plants. On extra cold nights, use two layers of row cover. Remove the row cover during the day, when it is above freezing, and place it back on at night.
There are three important environmental factors to consider for early-spring planting: Plants need at least 10 hours of sunlight a day for optimum growth. We started getting 10 hours in mid-January, so lack of daylight is not a factor by March. Vegetables can start to grow again, and barring any devastating deep freezes, they will continue to grow and you can get cold-hardy crops earlier this spring.
Lots of cold-hardy vegetables germinate in cold soil. They will be slow to start at first, but they will grow as your soil warms up to 40° F andwarmer. Many of the cool-season vegetables don’t like our springs, when one day is cold and the next warm. Warm days cause bolting (when plants think they are done and put out flowers). Plants that bolt are bitter-tasting. The good news is that by planting early, you’ll be able to harvest that spinach before it bolts! A soil thermometer can help in determining when to plant.
Air temperature is the main thing people think about in considering when to plant cool-season vegetables. Some crops are very cold hardy, many even below32° F at night. That said, if you don’t have a cold frame and will be planting outside in early spring, definitely use row cover at night, and don’t forget to check your soil temperatures before planting.
Some cold-hardy crops may freeze at night even with row cover. This might not be a problemprovided it isn’t a really hard freeze and they are allowed to thaw during the day. Plants must be completely thawed before you harvest them. Watering is necessary to get crops started, but they will generally need very little water during the early spring, once established.
Now is the time to plant all these great vegetables and enjoy an early start to the growing season.
Jannine Cabossel, the Tomato Lady at the Santa Fe Farmer’s Market, is a Master Gardener and teaches many classes around the city. To find outmore about gardening in our high desert, visit her blog at www. giantveggiegardener.com.