In the Garden | Arbor Day tree and shrub distribution is April 13

Bonnie Orr, master gardener

It is the end of April, and people in the greater Wenatchee area often plan to plant a garden as a way to celebrate Apple Blossom, which gets underway this week.

There is nothing more satisfying than planting a seed and watching it develop. That is what gives us gardeners inspiration. On the other hand, having seeds fail to germinate causes us to despair over our gardening talents.

There are six considerations that will enhance your success at direct sowing of seeds in the garden.

1. Remind yourself that gardening is not a competitive sport. And, having the first tomato or ear of corn has never been awarded a silver cup.

2. The soil must be warm enough for seeds to germinate. This is the most important step. We are so excited at the end of April because the days are sunny and have warmed into the 60s and 70s during the day. Alas, they often cool into the 40s at night. This means that the soil is slow to warm.

When we create a family day of garden planting, it is usually a marathon. Everything gets planted in rows, or groups — but the soil is not warm enough for everything to be planted at the end of April. In fact, many seeds should not be planted until June.

How can you determine your soil temperature? Use an instant read digital thermometer with a 6-inch probe. You can buy them anywhere kitchen wares are sold. Or visit the website  for Agweathernet at Washington State University. You have to sign in to a create an account, but it is free.

If the temperature is too low, the seed absorbs soil moisture but can’t germinate, so it rots, or it germinates and dies. Cold soil can also lead to a fungal disease such as “damping off.” That is why many people have to re-plant an early garden because of spotty germination.

The practical side of taking into account soil temperature is ensuring better seed germination. When the soil is 41 degrees, lettuce seeds take 15 days to sprout. When it 68 degrees it takes three days. This is why a fall garden planted on Aug. 15 gets started so rapidly.

A minimum temperature of approximately 45 is great for beets, cabbage, Swiss chard, spinach, radish and peas.

Corn and beans require a minimum soil temperature of 70 degrees, which will most likely not occur until the end of May. Muskmelon, pumpkin, cucumber, squash and eggplant all need a minimum of approximately 65 degrees. However, they will germinate more successfully when the soil is 80 degrees.

Flower seeds also have set point temperatures. For example, Nasturtiums sees germinate when the soil temperature is 55 degrees.

Zinnias need consistent night temperatures above 50 degrees before they will germinate.

3. Plant seeds at the correct depth. Seeds planted too deeply don’t have enough reserves for the sprout to find its way to the surface. Many small seeds barely need to be covered.

4. Firm the seeds into or onto the soil — depending on the seed size. Then water gently. The seed must be in contact with the soil and there should be no drying air spaces around the seed.

5. Keep the soil surface damp until the seeds have germinated. Seeds drying out is one of the reasons that they fail to germinate. You can keep them moist with a thin layer of peat moss that is dampened each day—or spread floating row cloth over the bed to slow down evaporation. The row cloth will also prevent birds and other garden pests such as squirrels or raccoons from snacking on the newly planted seeds.

6. Be bold and thin the seedlings so you create strong, vigorous plants. Seedlings that are growing too close together compete for water, light and root space. And none of them thrive. The back of the seed packet tells you how far apart the plants should grow. Try setting the seeds out on a damp strip of paper towel placed on the soil to help you see the seeds and space them so not to waste seedlings that you have to thin out.

Enjoy your garden this year.


A WSU Master Gardeners of Chelan County column appears weekly in The Wenatchee World. Bonnie Orr is one of three columnists featured.