Growing plants from seeds can be a rewarding experience

“The joy of growing plants from seed — is the challenge of getting them to germinate,” says Carol Small, plant propagator for Nichols Garden Nursery in Albany.

Small has a bachelor’s degree in horticulture from Oregon State University and is a Benton County Master Gardener, who really digs her job propagating plants from cuttings as well as seeds.

She has worked at Nichols since 2000 and this is her fourth year in the greenhouse where 90 percent of her work is taking cuttings. However, she is also passionate about growing plants from seed.

If you want to get a head start on the growing season — now is the time to start many seeds indoors.

“It’s a mystery that a tiny seed can pop up into this gorgeous plant,” Small says. “It’s amazing.”

Germination

The goal of growing seeds is getting them up and out of the ground, Small says. But different seeds need different conditions in order for that to happen.

Four environmental factors affect germination: Water, oxygen, light and heat. Her best advice is to read the seed packet first. It should provide germination and cultural tips for you.

Once the seed has germinated, letting the soil dry out around the embryo will kill it, so constant moisture is important.

Putting a plastic bubble dome over the germinating seeds helps keep the soil moist. Watering seed trays from the bottom helps avoid the dreaded “damping off” disease, a water-borne fungus. (Tip: if you see this starting, Small suggests you remove seedlings around it also to prevent the spread of this disease or you can loose the whole tray.)

An establishing embryo also requires oxygen to convert stored carbohydrates into energy (respiration). Loose and well-aerated soil allows for better respiration.

Light and bottom heat are particularly important for seed starting, says Small. Seeds that need light to germinate can be sprinkled on top of the soil or lightly covered with fine peat moss or vermiculite.

Seeds that need the dark should be planted under the surface by an inch or so of soil. Generally speaking, a temperature range of 65 to 75 degrees is best to get seeds to germinate. Placing the germination flats on top of heating mats or on top of the water heater if you do not have a mat will increase your chances for success.

“Use your imagination on what’s warm in your house,” Small says. “Close to a woodstove works for me this time of year.”

Examples of many plants that need light to germinate are zinnias and marigolds (annuals) and salvia and pansies (perennials). Sage seed has a chemical in the coat that has to be washed off to get it to germinate. In the desert where it thrives in sandy soil with not much water the seeds require rain to germinate. This little miracle happens only when there is enough moisture available to support the plant throughout its establishment — from sprouting to having the first couple of leaves — and enough root system to actually tap into the surrounding water source.

Vegetable seeds typically like the dark (underground) to germinate. Exceptions are lettuce and carrots. These need only a light dusting of soil and constant moisture in order to sprout.

Carrots don’t like transplanting so they need to be sowed directly into the garden. To keep the soil moist enough, my dad put a wet burlap sack over the row of carrots and keep it moist until the tiny sprouts started popping up, then gently remove it. I’ve also heard of gardeners who use a (one-by-four) board the length of the row to gain the same moist conditions.

According to the Territorial Seed Company planting chart, vegetable seeds that could be planted indoors now include asparagus (12/15-3/30), artichokes (1/1-5/1), peas (2/15-6/15), broccoli, brussel sprouts, cabbage, cauliflower — all (3/1-4/30), eggplant, peppers, and onions (3/15-5/1), and lettuce (3/15-8/1), to name a few.

Seed viability

To ensure that your seed comes up — buy good seed, but only enough for the season you are planting in. Even then only about 65 to 80 percent will sprout. If you do have any leftover seed, keep them in their original packets in your refrigerator’s vegetable crisper in a sealed ziplock bag.

A technique Small uses to determine if a seed is viable — such as sweet peas, corn and squash — is to put a few seeds between two sheets of a wet paper towel in a ziplock bag till they sprout (Tip: Keep them on the kitchen counter so you remember to check them often.

Seeds that don’t like their roots disturbed can be started indoors if you plant them in a cardboard egg carton or in rolled newspaper strips — something that will disintegrate when put in the ground. Once established with a set of second leaves each individual cell can be easily separated to not disturb the delicate young roots.)

Hardening off

Before you plant your seedlings in the garden, you will need to harden off the young plants to get them used to outdoor growing conditions first. Hardening off is the process of taking the young plants in and out over the course of a few weeks, starting with a half a day out — being sure not to place young seedlings in direct sunlight for the first few days. Increase the length of time and sunlight exposure every couple days.

If your seedlings are a bit leggy and you do not have a fan running in your greenhouse, Small suggests gently brushing your hand over the germinating plants to simulate a breeze. This strengthens the plants to withstand wind and rain events.

Before you harden seedlings, Small recommends decreasing the amount of water you give them. This will stimulate food production. But remember not to fertilize seedlings until they have at least two sets of true leaves, they are too sensitive.

Dormancy function

One of the functions of dormancy is to prevent a seed from germinating until conditions are favorable. The seeds of some trees and shrubs are really selective this way and some go one step further. They need to be scarified, which means the surface needs to be nicked or scratched in order to germinate (curry trees and avacado trees are examples). Some seeds need the heat of a forest fire to break dormancy, and others need cold stratification — where you’re actually mimicking its natural conditions with periods of cold.

Stratification can often be accomplished by simply putting the seed packets in the refrigerator for several weeks (asters, echinaceas and pansies are examples). Joy Pye and flaxinella need to be planted in soil in small pots first (Tip: Make sure to label these so you don’t forget what you planted) and covering them with a plastic bag to retain moisture. Keep this in the refrigerator for 4 weeks and out for 3 weeks; repeat as needed.

Small recommends “The Gardeners A-Z Guide to Growing Flowers from Seed to Bloom” and “Grow Organic Vegetables” to help you get started. Check your local nurseries or garden centers for availability.

Also check out the OSU Extension website www.eesc.orst.edu for brochures on this and other related topics:

EC 1228 — Planning and Preparing Your Vegetable Garden Site.