February garden checklist

UNIVERSITY OF MINNESOTA EXTENSION - www.extension.umn.edu

Mystery of the month

Four weeks ago, you started seeds collected last fall from a swamp milkweed in your yard, and they have not germinated. You used the ideal potting mix and container and kept the potting mix moist and warm. What could be the reason the seeds did not germinate?

The solution is at the bottom of this article.

Pests and diseases

Notice tiny black flies hovering around your houseplants or near lights and windows? You may have a fungus gnatinfestation. Fungus gnats thrive in wet soil. To reduce their presence, you can evenly apply a 0.5-inch layer of horticultural sand to the top of your containers. The sand will dry faster than the soil beneath it, preventing new fungus gnats from laying eggs in the soil.

Read more about managing insects on indoor plants.

Trees and shrubs

Tap your sugar maple, silver maple, box elder, and black walnuts to create homemade syrups. The tapping season has just started in the southern portion of the state.

Watch these Hort Shorts to see how to tap maple and black walnut trees and collect the sap using bags.

Flowers and other garden plants

You can start some garden plants indoors this month. Some perennial and annual flower seeds need to be started 12-16 weeks before they are large enough to transplant in the garden. We created a great table of when to plant seeds of various flowers and vegetables.

Many seeds of our native perennials require a cold, moist period to germinate. You can mimic winter conditions by placing seeds in a refrigerator; all you need is a container, moist towels, seeds, and room in the fridge.

Houseplants

Start fertilizing houseplants more regularly if you stopped fertilizing over the winter. As days get longer, plants will use more nutrients to grow.

Read and follow all instructions on the fertilizer container label.

Lawn

Lawns are unlikely to grow for several weeks, regardless of whether there is more snow cover. It can be tempting to get out and do some spring cleaning.

Try to avoid doing too much, like aggressive raking or dethatching. This can stress the lawn and create voids where annual weeds can establish.

Let the lawn wake up on its own.

Other tasks

Check your trees and shrubs for signs of animal browsing. If you see a stem with much of the bark removed, you can safely prune it now.

If the damage happens to be on a forsythia, willow, or another spring-flowering shrub stem, try forcing the blooms indoors for a colorful floral display.

Solution to the mystery of the month

Some seeds require a cold, moist period before they can germinate — this is called cold stratification. In nature, this process happens naturally during winter. When we start seeds indoors, we must mimic this environment. 

If you want to start seeds that require cold stratification, all you need is a container, a moist (not wet) substrate, a fridge, and the seeds.

Pictured is a petri dish with tamarack seeds on moist filter paper. This dish was kept in a dark drawer at the back of the fridge for two weeks before the seeds were sown in pots and moved to a greenhouse.

You do not need to use petri dishes. Sealable sandwich bags, opaque containers, or any sanitized container can be used to stratify seeds. When you look up the process for germinating seeds with a cold stratification, you will see a specific number of days or weeks that the seeds need to be stratified. Make sure you account for that time when counting the number of weeks until the seedlings can be transplanted outdoors.