Harden off your starts before planting outdoors

Seedlings need time to adjust from indoor to outdoor growing conditions

As I wrote in Sunday’s column, gardening is an exercise in delayed gratification. We experience the joy of watching plants grow, flower and fruit, but we must wait to harvest and eat the food, unlike going to the grocery store or farmer’s market.

Even before planting seedlings in the garden, we should practice patience by hardening off those we have grown from seed indoors. This process involves gradually exposing the seedlings to outdoor conditions over a week-long period so they get used to sunlight and temperature changes.

Once your seedlings have 2-3 sets of true leaves (this means not counting the cotyledons) and a well-developing root system, they are ready to be transplanted into the garden. (Make sure your bed is cleared of debris and you have amended the soil with fresh compost to replenish the soil.) Move your trays into a filtered shady spot (avoid direct sunlight) for a few hours during the first day, and then gradually increase outdoor exposure by a couple of hours each day until the plants are fully acclimated by the end of the week.

After a week, if the weather stays above 40 degrees, begin leaving the plants outside for a few days. Keep floating row cloth handy and use as needed (I use mine for the first night). Continue monitoring the moisture level in the trays, and keep an eye out for chewing insects (such as earwigs!).

When transplanting seedlings grown from seed in the greenhouse, use a teaspoon and gently scoop out the young plant along with all the soil in the cell. Place the plant gently into a hole with the roots dangling down, and if you must handle the plant do so by its leaves, rather than the stem or the roots.

Fill the hole with soil and firmly press down so there are no air pockets around the roots. Water new plantings and top with a thin layer of mulch to retain moisture and reduce weeds. Keep the row cover handy and use as needed for chillier-than-expected spring nights.

Don’t forget to label your plants! I know you think you’ll remember what they are, but you won’!

Happy gardening!


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