How to Start Broccoli Seeds Indoors

Broccoli is a cool season plant and one of the first vegetables to be transplanted outdoors in the spring. Starting the plant indoors ensures it has enough time to mature before summer temperatures arrive and it becomes too hot for broccoli to produce further crops. Start broccoli seeds seven weeks before the last expected frost date in your area. Transplant into the garden one to two weeks before the last expected frost date in your area so they get a maximum of growing time during cool spring weather.

Pots

Peat moss

Compost

Sand

Plastic wrap

Grow lights

Fill seed starting pots with a seed-starting potting soil. Make your own by mixing equal parts of compost, peat moss and coarse sand.

Sow seed in the center of each pot to 1/2-inch depth. Water the soil until it is evenly moist after planting.

Cover the pots with plastic wrap to preserve soil moisture. Place the pots in a 55- to 65-degree Fahrenheit room to germinate, approximately seven days.

Remove plastic once sprouts appear. Move to a warm, sunny window sill or place under grow lights. There should be 3 inches of space between the top of the seedlings and the grow lights.

Keep the soil moist but not soaking wet until you transplant. Water as needed to maintain soil moisture.

Harden off seedlings for one week prior to transplanting outside. Set pots outside in a protected area for two hours the first day. Increase the time outdoors each day for seven days until they are spending the full day outside.

Broccoli can also be direct seeded in the garden under cold frames.

Start fall broccoli crops indoors in mid- to late-July. Transplant outdoors when the seedlings are two weeks old.

Do not start broccoli seeds indoors too soon, or the plants will not thrive.

Broccoli seedlings are prone to damping off, which is caused by fungus. Avoid over-watering and provide enough light to help prevent this. Dispose of any potting soil from plants that succumb to damping off.