SOIL Blocking method helps grow seeds

Gardeners can use the method to begin growing their plants indoors while the weather is still cold.
KNIGHT RIDDER NEWSPAPERS
NEWPORT NEWS, Va. -- If you've ever held celosia seeds in the palm of your hand, you know just how teeny tiny they really are. You can comfortably hold several hundred of them at a time.
Sowing celosia seeds in a large, open germination tray can be next to impossible. It's tedious to separate them so they can sprout and begin life as healthy transplants for the outdoor garden.
Cut-flower grower Lisa Ziegler knows the trick to dealing with them and other kinds of seeds for better homegrown blooms.
She uses a technique called "soil blocking" to create different-sized individual squares of potting soil.
"This is the way many English gardeners grow their plants," said Ziegler. In the early 1990s, she began growing all sorts of cut flowers for florists and retail sales at her home in Virginia.
"I had horrible success with other seed-starting methods.
"I've started 75,000 seedlings this way and never had any damping-off problems." (Damping-off is a common fungal disease that attacks seedlings, weakening the stems at the soil level.)
Ziegler's first introduction to blocking up soil came from Eliot Coleman and his book "The New Organic Grower."
"He's the most practical man," she said. "Any serious gardener needs to have his book."
How to do it
To create soil blocks, you first need very wet potting soil. Ziegler uses a black plastic tray that's 6 to 8 inches deep and a wooden-handled potato masher to get the consistency she wants.
"This is the best tool to use," she said, pushing the old-fashioned mashing utensil through the water-heavy soil.
"It's like mixing concrete."
She then uses 3/4-inch or 2-inch blockers to form soil blocks. The blockers are wooden or plastic forms that you insert and wiggle around in the tray of wet soil. When you feel like your blocker is filled with soil, you give it a gentle squeeze to release and push the blocks of soil onto something flat like a large plastic serving tray. You can even use plastic foam meat trays to hold the soil blocks. Seeds are then dropped into the small indentations automatically formed during the blocking process.
"The better the quality of your block of soil, the better it holds up over weeks of watering before you take it out to the garden to plant," she said.
Once the blocks of soil are outfitted with seeds, Ziegler uses bottom heat mats and artificial or natural light to get her seeds to germinate. She's done this process in the basement with overhead fluorescent lights, so she knows you need no fancy greenhouse conditions to be successful.
"Look at these roots, these are fabulous," she said, showing a multitude of healthy white roots filling the block of soil on 2-week-old zinnias called Benary's Giants. Typically, these zinnias have a 75- to 90-day maturity from seed to bloom.
Starting the seeds with soil blocks gets Ziegler faster results.
"With this method, I can harvest zinnias 40 days after setting them in the garden, and that's some good growing."