Spring Gardening Tips

Hints on how to harden-off plants for spring planting.

  • Topic: Spring Gardening
  • Keywords: hardening, frost, spring, , Planting Techniques, gardens
  • Date: April 2001

© All articles are copyrighted by High Country Gardens. Republication is prohibited without Permission.

As the season moves a little further into the spring and the ground begins to thaw, we go from early spring clean-up time into planting time. Woody plants (trees and shrubs), cold-hardy perennials and frost-resistant annual flowers like Pansies, Snapdragons, and Calendula can be safely planted before the danger of frost has past. Remember that even the most cold hardy plants will need some hardening before they can hold-up to freezing temperatures.

Hardening Plants Before Transplanting

When transplanting plants from the greenhouse (where they are in active growth) into the garden, the plants must first be conditioned to withstand intense direct sunlight, drying winds and freezing temperatures. This process is called “hardening” and takes 7 to 10 days to accomplish.

To begin, take the plants outside to a protected porch or patio during the day. Gradually increase the amount of sunlight they receive, starting with just an hour or two for the first three days. After that move the plants so they are in the sun a bit longer each day. By the end of the hardening process the plants should be in the sun most of the day. If the weather forecast calls for freezing temperatures, bring the plants in at night. If not leave them outside.

I like to mist the foliage with the Saltwater Farms liquid seaweed every few days spraying the leaves top and bottom until the water drips off the leaf surface. Using liquid seaweed greatly improves the hardening process! Note that we mark the perennials we ship that come out of the greenhouse and need to be hardened with “I’m a tender plant” tag.

Dormant Plants

Dormant plants or plants that are being grown in unheated cold frames can be placed directly into the garden without hardening. In very windy, exposed planting situations I have found it very beneficial to provide the plants with some wind protection.

Place a “Wall-of-Water” insulating tube around the plant, wrap some frost blanket material around a tomato cage and place over the plant or push a gallon plastic milk jug (with the bottom cut off and screw cap removed) into the soil to cover the plant. Leave the protection in place until the worst of the winds have past. These wind protection devices can also help fend off browsing animals.

Don’t take shortcuts when planting

When your plants are ready to be planted remember two things. In addition to enriching the soil, mix a half teaspoon of Soil Moist water-absorbing crystals into the planting hole and water in the new transplants with the root stimulator combination of Saltwater Farms liquid seaweed and SuperThrive. I’ll admit that in past years I didn’t always take my own advice much to the detriment to some of my new transplants. It was Humberto, my staff gardener who reminded me that we were having to replant some of those plants. Now he and I always use the P4 and “Root Stimulator Combo” when planting.