Gardening in a short season can be unpredictable, tricky, and discouraging. Zone 3 gardeners are no stranger to these woes. Do I plant in early May? Wait until June? Will I be covering every night? Will it be warm enough? Follow this guide to learn all about what seeds to plant or sow indoors in March to kick off your gardening season! If you are pre planning, check out my guide on April seed starting as well!
Tips + Tricks
Starting seedlings indoors will help you to make the most of a short growing season! Do a little bit of searching to find out the average first and last frost date in your area.
In Northern Alberta our last frost date is usually between May 21-31st and the first frost date in the fall is between September 1st and 10th. The best reference for when you should plant individual seeds is the back of your seed package or the website that you ordered them from.
Packages will often advise you to plant ‘x’ amount of days before last frost. Know your frost dates! PlantMaps.com is an awesome resource to indicate your growing zone and your frost dates.
Pre-plan where you are going to put all of your seedlings before planting them. You don’t want to run out of table space after having to re pot different plants!
Use soil blocks in to produce healthy seedlings that can be started in close proximity. Check out my newest tutorial to discover how to mix, pack, and press soil blocks of various sizes easily.
Two Phases of March Seed Starting in Zone 3.
March Seed Starting Plant Information:
Broad beans: Give your broad beans a head start! They can be direct sown between February and May; however, it is a good idea to start the seedlings early for success.
Broccoli: Many species of broccoli take up to 100 days to reach full maturity! Maximize your growing time by sowing them in early March.
Brussels sprouts: These sprouts take 100-120 days to reach full maturity. Yikes! Start early for best results.
Celeriac: Celeriac can take from 20-30 days for germination alone. Seedlings are delicate and thrive when being started in a controlled environment.
Celery: Did you know celery can be chopped above the ground and regrown from the same base plant? Start early for two harvests!
Peppers: Peppers generally are slow to start, sometimes requiring heat mats and other special equipment. It is best to start them early to account for long germination times and slow growing seedlings.
Eggplant: Eggplant like warm weather. They can take up to 80 days to reach full maturity in ideal conditions. Start in March or April.
Leek: On average, leeks take 100 days to reach full maturity.
Onion: It is generally recommended to sow onion seeds in March while bulbs can be directly sown into the garden when you are ready to plant.
Tomato: No matter the type of tomato, it is always a good idea to start early to increase final tomato size and to give the plant time to ripen.
Strawberries: Strawberry seeds can be started at this time or as early as December.
Endive/ Raddichio: In general, raddichio take around 85 days to reach maturity.
Herbs: Herbs can be finicky to start and take a long time to show substantial growth. Start early to have the highest yield.