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Give your seedlings a healthy head start

Sun., April 15, 2012

These plants are eagerly awaiting their time in the sun. (Susan Mulvihill)
These plants are eagerly awaiting their time in the sun. (Susan Mulvihill)

So you’ve started your plants from seed and have been lovingly tending them the past few weeks. Now what?

Here in the Inland Northwest, the average last frost date is May 15. If you plant any of your tender seedlings – plants like tomatoes, peppers, eggplants, squash and most annual flowers – before that date, they might meet an untimely end.

To protect seedlings, there are steps you can take to ensure all of our nurturing efforts are worthwhile:

Harden off the seedlings to get them acclimated to the weather. This involves taking plants outdoors the week before you plant them in the garden. On the first day, they’ll just be outside for an hour before being returned to the controlled conditions of your home. Increase the time of these little field trips by an hour each day.

  • Don’t let the plants get sunburned. You probably thought only humans got sunburned, right? Actually, the seedlings’ leaves are quite delicate and won’t be used to the intensity of the sunlight at first.

 I’m embarrassed to admit this but I’ve been guilty of this very offense in years past. I’ve gotten excited about warming trends and moved plants right out into the garden to begin their new lives outdoors – only to discover, a day or two later, that their previously green leaves have burned to a pale white color. It won’t necessarily kill the plants but it certainly will set them back.

 The better way to handle this is to make sure they are under a cover or in the shade to lessen the intensity of the sun. If you’re in the process of hardening off the seedlings, put them under a lattice or shade cloth for the first few days. If it’s warm enough to plant the seedlings in the garden, a shade cloth or row cover will provide them with some protection while they’re getting used to the sunlight.

Protect seedlings from the wind as well. Some plants, like squash and melons, have very succulent main stems that can snap in two in the wind. Unfortunately, there’s no recovery from a calamity like that. If you are hardening them off or have planted them in the garden, protect them from the wind until their stems grow stronger.

One way to do this is to stand up a wooden shingle or small board next to the plant on the windward side. Or you can cover the bed temporarily with a floating row cover or shade cloth.

I use row covers quite a bit in my vegetable garden. This lightweight, spun-bonded fabric lets in air, light and moisture in addition to providing plants with a protected environment. Row covers also act as insect barriers and are what organic farmers typically use to keep damaging insects like aphids, cabbage loopers and leaf miners off their susceptible crops.

Another useful aspect of row covers is that they provide frost protection down to about 28 degrees. They can be found at large garden centers or online.

Heavyweight row covers – also referred to as frost blankets or garden quilts – protect plants down to about 24 degrees. Mail-order businesses that sell them include Johnny’s Selected Seeds (, Gardens Alive ( and Harris Seeds (

Just don’t leave row covers over plants that will need to be pollinated later. Remove the covers from tomatoes, squash, melons, pumpkins, eggplants and peppers once the weather is reliably warm so the bees can work their magic.

Susan Mulvihill can be reached via email at Visit her blog at for more gardening information, tips and events.

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