Master Gardeners of Northern Virginia

Over 40 Years of Growing Gardens and Gardeners

Snow covered branches
Photo © Mary Free

March is  the Time to Start Seeds Indoors

It’s easier than you think.

by Extension Master Gardener Nancy Dowling

🥕🍅 Welcome to a new column on vegetable gardening from veteran EMG Nancy Dowling,
a former coordinator at the MGNV Organic Vegetable Garden. 👩🏼‍🌾

If you like to be able to choose exactly the vegetables you want to eat and grow in your garden, March is the time to start your seeds indoors.  You will need sterilized seed starter mix, water, seed starting trays, ventilation, and lights.  See my set up, below, just started this month (March 9).  I’m monitoring my results so you can follow along.

Make sure you wet your soil mix in a container so it is moist, but not overly wet.  Then put the soil into the pots or seeding trays, making sure that you haven’t left any air pockets but don’t pack down too firmly. 

Any hardware store sells light fixtures you can use for this purpose.  I used “S” clips to attach to the shelves above to hold them in place.  Use lights that most approximate daylight.  Warming mats are also important to germinate seeds quickly.

A metal shelving unit with several pots of seedlings on the top shelf and seedling trays covered with plastic domes on the lower shelves, positioned by a window with natural light.
Seedling tray setup Photo © Nancy Dowling
Seedling tray with various plants labeled 'San Marzano', 'Cherokee Purple', 'Yellow', 'Black', and 'Lobelia', showing young sprouts in soil.
Seedlings just beginning to sprout. Photo © Nancy Dowling

Seedlings pop out in about a week (around March 15th) and from then on, all that’s needed is diligence:  water, turn the lights on in the morning and off at night, and keep air circulating.  It helps if you have a fan blowing on low in the room if things get too hot or stuffy.  

The best thing about starting your own plants from seed is that YOU get to choose the cultivar you want to grow.  For example, I wanted large slicing tomatoes as well as tasty ones for sauces, and cherry tomatoes for salads.  I chose German Johnson, Black Krim, San Marzano, and Yellow Mimi.  All but the Yellow Mimi sprouted by March 22nd. 

By the first week in April, some of these seedlings will grow their 2nd set of leaves and can be transplanted into bigger pots.  This is best done using a sterilized transplant mix or potting mix.  They still need light, air circulation, and water from below just like they did as seeds.  But now you are preparing them for the hardening off process.  In two weeks, they can be placed outside on a warm, sunny day for 4 hours, increasing a few hours every day to acclimate to the real world.  After two weeks of this, they can stay out until you are ready to plant them in the ground.

Tomatoes, peppers, and eggplants are excellent to start in mid-March.  Tomatoes can be either determinate or indeterminate. Determinate tomatoes only grow to a finite height, grow their fruit for a limited time, and then wither, but most of your big juicy tomatoes are of this variety.  This works quite well for small spaces.  The smaller paste and salad tomatoes are indeterminate and will grow higher than you can reach and require support. These indeterminate tomatoes are prolific and need space for both width and height.  Given the right amount of water, temperature, and space, they can produce fruit into November in our region.

For more information, see Virginia Cooperative Extension resources about seed propagation: