What You Need To Start Seeds Indoors

You have to invest a bit to create the proper environment to initiate and nurture vigorous young plants, but it’s simpler and more affordable than you might think.

December 23, 2015
seed tray

Gathering the right equipment before you begin sowing takes much of the gamble out of starting your own seeds. Preassembled kits tend to be pricey and inflexible. They’re also unnecessary. If you know the components of a successful seed-starting station, you can customize it to your space and scale it to meet your garden’s needs. Here’s a breakdown of what you’ll need.

Heat Source
Keep heat-loving seedlings warm with a waterproof heat mat that fully accommodates the bottom of your seed tray. Most mats designed for seed-starting, like the 9-by-19½-inch Hydrofarm, will heat a seed tray to about 20 degrees above the ambient temperature. Do not use an electric blanket or regular heating pad, because those can be dangerous when you’re dealing with a setup that requires water. 



Cell flats are the vessel of choice. Durable and reusable, the space-efficient trays allow you to fit 100 or more seedlings under a standard 4-foot fluorescent light box. They’re also relatively inexpensive. Start with a five-pack of 50-cell flats. Add on leakproof bottom trays for postgermination watering. When it’s time to transplant seedlings that have outgrown the cell flat, move them to biodegradable containers like 4-inch CowPots, which greatly reduce transplant shock and decompose quickly when sunk into the soil in your garden. Cell flats and trays are reusable; be sure to clean them well and then rinse them with distilled white vinegar to sanitize them between uses. 

All-purpose potting soil is generally a poor choice for seed starting. Instead, go with a mix tailored to the specific needs of young plants, such as Organic Mechanics Seed Starting Blend, a sustainably sourced mix of coir and rice hulls that retains the right amount of moisture, plus composted pine bark and worm castings for slow-release nutrients that promote healthy seedlings. 

Related: Behind The Scenes At Organic Mechanics Soil Company

Irrigate your freshly sown cell flats with a spray bottle on its finest mist setting until most of the seeds have germinated. Top each tray with a humidity dome to keep the environment hydrated.

You can store seed flats on a ready-made, lighted grow station like the Stack-n-Grow Light System, but these get costly as you add on units. For a DIY way to get bigger, buy a 4-foot-wide, four-shelf adjustable wire-frame unit, which can hold eight 20-inch flats. Fit it with 4-foot, two-bulb fluorescent fixtures with S-hooks and chains for adjusting their height ($27), furnish the fixtures with full-spectrum bulbs, and connect them to a good timer for consistent daily light.


Seed Shopping

January’s best reads are seed catalogs. Filled with lush photos of plants to grow from hybrid (controlled) and open-pollinated (naturally produced) seeds, they sow inspiration. 

Adaptive Seeds sells open-pollinated (OP), organic seeds chosen to thrive in the Pacific Northwest. 

Fedco Seeds in Maine offers organic heirlooms and hybrids that do best in Northeast gardens. 

High Mowing Organic Seeds offers 600 organic varieties, some of them grown on its 40-acre Vermont farm. 

Native Seeds/SEARCH is a good source for drought- tolerant varieties, including lots of dent and flour corn and beans. 

Seed Savers Exchange, a pioneer in heirlooms, offers fascinating OP vegetable and flower seeds, many of which are organic. 

Select Seeds specializes in old-fashioned and unique heirloom flowers, including organic ones. 

Southern Exposure Seed Exchange emphasizes Southern crops like crowder peas, okra, and peanuts. 

Thyme Garden Herb Company sells an impressive array of herb seeds and plants, all organic, for culinary and medicinal uses. 

TomatoFest, true to its name, has 600 varieties of certified-organic, OP tomatoes. 

Turtle Tree Biodynamic Seed Initiative offers biodynamically grown OP seeds. 

Tags: How-Toseeds