Starting perennials from seed

By Dawn Pettinelli - UConn Home & Garden Education Center
Feature Article - posted Fri., Feb. 25, 2011
- Contributed Photo

Perennial plants play major contributing roles in many gardens. Their flowers are varied in color, shape, size and season of bloom. Many are long-lived, coming back year after year more lush and beautiful. Garden designers generally recommend planting perennials in groups and repeating these groupings throughout the bed. This sometimes calls for a large number of plants, and thus, a rather large price tag.

Many perennials, however, are no more difficult to start from seed than annual flowers or tomatoes. This is an extremely cost-effective way to create colorful displays for a minimum of monetary investment. The one disadvantage of growing perennials from seed is that you sometimes get variable plants. They may not all be of uniform habit due to some inevitable natural variation, but I feel that’s part of the excitement of starting plants from seed.

Seeds of some of the more common, easily-grown perennials can be found in many seed catalogs and also in the seed racks at many local garden centers. I start several varieties of perennial plants from seed each year. Some of your best bets are yarrow, coreopsis, hollyhocks, coneflower, Shasta daisy, candytuft, veronica, liatris and penstemon. If this is your first time growing perennials from seed, you probably should avoid those species which require a chilling period or scarification. There are a few books available that have tips on seed-starting, but you should also find information on germination requirements on the seed packets themselves.

Successful seed-starting begins with clean containers, a growing media specially formulated for seed-starting, and a well-lighted growing area. Always moisten the media with warm water before filling shallow flats or small pots. Fill the container almost to the top for good air circulation. Pat the media down lightly and sprinkle seeds evenly. Usually, I place two seeds in each cell and keep the healthiest looking seedling if both seeds germinate.

Check seed packets to see if light or darkness is required for germination. Seeds that need light for germination are just lightly pressed into the medium. Those that require darkness can be covered with a little more seed-starting mix. After planting, I use a mister to thoroughly moisten the top half inch or so in each container. Be sure to label your containers. I usually keep a seed-starting journal.

Germination temperatures are also usually listed on the seed packets. Most of the perennials I have mentioned germinate well at temperatures around 70 degrees F. I like to place the flats or pots into the larger black plastic trays with clear plastic dome lids, creating a mini-greenhouse-like environment. Humidity levels remain high, and little, if any, additional water is needed before the seeds germinate.

Place the large trays in a warm spot. Some serious hobbyists opt to use heat mats under their seed containers. Avoid setting the tray in direct sunlight, because temperatures can become too high with the clear plastic tops on. As seedlings emerge, either remove individual pots if you are growing perennials with differing germination times, or take the clear lid off if all are coming up simultaneously.

Place the young seedlings under fluorescent lights or in a sunny windowsill. Keep the media moist and fertilize with a low-phosphorus, quarter-strength, water-soluble fertilizer every seven to 10 days or so. When four true leaves appear, seedlings can be transplanted into cell packs or small, individual pots. Be sure to harden transplants off before planting in the garden.

Starting perennials from seed can be a very rewarding, not to mention money-saving, venture. For more information about seed starting or other topics, call the UConn Home and Garden Education Center, toll-free, at 877-486-6271, visit the website, or contact your local Cooperative Extension Office.


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