Starting seeds properly can make or break your entire growing season! Here are our best tips and tricks for starting seeds indoors.
Before You Start Seeds
- Be seed savvy. Obtain seed catalogs from several companies and compare their offering and prices. Some of the regional companies may carry varieties better suited to your area.
- Make a list of what you’d like to grow. A good rule-of-thumb is to imagine your garden one-quarter the size that it really is. This allows for good spacing practices! See our Growing Guides for inspiration.
- Prepare for some losses. Though it’s good not to plant too much for your garden space, it’s also good to assume that some of your seeds won’t germinate, or that they will inexplicably die off later. Plant a few extra, just in case.
- Team up with a neighbor and share seeds if you have leftovers!
- Don’t start your seeds too early, especially tomatoes. Most annual flowers and vegetables should be sown indoors about 6 weeks before the last frost in your area. Check out our Planting Calendar to see when to start seeds (indoors and outdoors) in your area.
- You may have to soak, scratch, or chill seeds before planting, as directed on packet.
- Use clean containers. Most seed catalogs offer seedling flats, peat pots, and other growing containers, but egg carton compartments make good containers, too. Be sure to poke holes in the sides near the bottom of the containers you use in order to allow excess water to drain.
- Label your containers now! There’s nothing more frustrating than forgetting what you planted.
How to Start Seeds
- Fill clean containers with a potting mix made for seedlings. Use soilless peat moss and mix in equal parts vermiculite and perlite to hold enough water and allow oxygen to flow. Don’t use regular potting soil.
- Pour soilless mix into a large bucket and moisten with warm water. Fill your containers to just below the rim.
- Plant your seeds according to your seed packet. Most seeds can simply be gently pressed into the mixture; you can use the eraser end of a pencil to push in seeds. When planting seeds, plant the largest seeds in the package to get the best germination rate.
- Cover containers with plastic. Prick holes with a toothpick for ventilation. Water as directed.
- Water newly started seedlings carefully. A pitcher may let the water out too forcefully. A mist sprayer is gentle but can take a long time. Try using a meat-basting syringe, which will dispense the water effectively without causing too much soil disruption.
- Find a place in the kitchen where there is natural bottom heat—on top of the refrigerator or near the oven. (Move the tray if the oven is on, as it may become too hot.)
- Seeds sprout best at temperatures of 65 to 75°F (18 to 24°C).
- When seedlings appear, remove the plastic and move containers into bright light.
- When the seedlings get their second pair of leaves, prepare individual pots filled with a potting mix with plenty of compost. Move the seedlings carefully to the new pots and water well. Keep pots out of direct sun for a few days.
Photo by Sergii Kononenko/Shutterstock
Moving Seedlings Outside
Before transplanting seedlings to your garden, you’ll first need to do something called “hardening off.” This will prepare the seedlings for the harsh realities (i.e., climate) of the outside world!
- During their last week indoors, withhold fertilizer and add water less often.
- Seven to ten days before transplanting, set the seedlings outdoors in dappled shade that is protected from winds for a few hours each day, gradually increasing their exposure to full sun and windy conditions. This is the hardening-off period.
- Keep the soil moist at all times during this period. Dry air and spring breezes can result in rapid transpiration. If possible, transplant on overcast days or in the early morning, when the sun won’t be too harsh.
Watch our video on hardening off for more info:
After the hardening-off period, your seedlings are ready for transplanting. Here are a few tips:
- Set transplants into loose, well-aerated soil. Such soil will capture and retain moisture, drain well, and allow easy penetration by seedling roots.
- Soak the soil around new seedlings immediately after transplanting.
- Spread mulch to reduce soil moisture loss and to control weeds.
- To ensure the availability of phosphorus in the root zone of new transplants (phosphorus promotes strong root development), mix 2 tablespoons of a 15-30-15 starter fertilizer into a gallon of water (1 tablespoon for vining crops such as melons and cucumbers), and give each seedling a cup of the solution after transplanting.
See when to start seeds in your area with our location-based Planting Calendar.