Garden Views: It’s a good time for starting plants indoors

The darkest days of winter have past and gardeners are thinking about the coming spring and the seeds that can be planted. Starting gardens from seeds gives more variety and more color choices and is not excessively difficult. Planning and timing are critical. Select vegetable seeds that ripen in the time frame you want. Tomatoes can be selected by varieties that ripen all at one time (determinate) or ones that ripen over many weeks (indeterminate). Tomatoes that ripen in a large group make canning more convenient.

Some annual flowers, like zinnias, can do fine by just planting the seeds directly in the ground, but many need an indoor start to bloom in our abbreviated summers.

For common plants, generic seeds can be inexpensive, but specialty plants or a new variety will cost more. Germination percentages will decrease over time, but most seeds are viable for 2 or 3 years or more if kept cool in air tight containers. Follow the planting directions on the packet.

Small individual containers are best, since it will help keep each plant growing separately. Wash thoroughly and disinfect any containers you are using from previous years by soaking the cleaned cups in a solution of bleach or other disinfectant for 30 minutes, then rinse and use. Mix the solution to the strength recommended on the label for disinfecting surfaces. Drain holes are essential to keep from drowning the seeds. Peat pots or other starter pots are also fine.

Seed starting mixes of peat and vermiculite are ideal. They are lightweight, weed free and ideally suited for seedling growth. Fill the containers with the growing medium you have selected and water well before you plant seeds. Let the soil soak up the water completely. You may need to add more soil and water again. Or you may wish to dampen the medium prior to filling the containers. Finally, add the seed.

Water, light and heat are needed for successful seed growth. Clear plastic over the plant containers helps keep moisture and humidity in while not blocking light. Some gardeners use specially designed heating pads underneath the containers for added warmth.

Natural light inside a house in the early spring is not enough light to successfully grow seedlings. You will need fluorescent lights; “grow” lights are not essential. A full spectrum standard fluorescent (shop light) will do nicely. Suspend the lights 2 to 6 inches above the trays and leave lights on 12 to 16 hours per day. A light weight chain works well to suspend the light. The chain makes it easier to raise or lower the light as necessary. A light timer is very helpful. Since you do not need a window, select a spot away from drafts from doors and away from heavy traffic. Basements are fine if air temperatures are above 60 degrees and the bottom of the seed trays are also warm. Consistently warm soil insures germination and strong roots. Avoid letting the soil dry out as this will kill seedlings. A spray bottle works well and does not overwhelm the seeds as they germinate. Fertilizer is not needed until several sets of true leaves have developed and then a weak water soluble solution at quarter-strength is adequate once a week. Once your plants have grown several inches, it also is advisable to have a rotating fan set on low to gently move your plants. This fan can be on for the same time duration as your lights. This movement will help develop stronger stems.

As anxious as we all are, do the prep work and planning now, but starting plants too soon will leave you with tall gangly plants that are ready to be put outside before the weather will permit.

Onions and leeks can be started in February along with pansies, begonias and geraniums. Wait until March to start broccoli and cabbage. Petunias, coleus, snapdragons, verbena and vinca can all be started in early March. Wail until late March or early April to plant tomatoes, peppers or eggplant.

Once the seedlings have developed true leaves, cut all but the healthiest one in each container off at ground level with scissors. If you try to separate and transplant seedlings, or try to just pull the unwanted seedlings out, you’re likely to damage the roots of the one you want to keep.

Two weeks before seedlings are to be planted outside, begin the hardening off process, getting the plants accustomed to being outside. Start in a shady location, out of the wind for several hours each day, bringing them in each night. Gradually add more hours of exposure and more sunlight. If night temperatures have warmed sufficiently after two weeks, leave plants out until you can plant them in your chosen location.

Use a spoon to help lift the plants from the cell pack containers to avoid damaging the plant. If you use peat pots be sure to sink the pot into the dirt so that the rim of the pot is below the soil line, otherwise moisture will be wicked away from the plant through the exposed rim.

If possible, transplant seedlings into your garden on a cloudy day or late in the afternoon. Direct sunlight can wilt even hardened off plants. If the wind is a problem, cut open gallon milk containers and make wind shelters for your plants. Avoid these if the temperatures are really warm as the plastic will accelerate and contain the sun’s heat. Happy planting!

Additional information on a variety of topics is available at the University of Minnesota website:

Barbara Harlan is an Anoka County Master Garden.


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