Build confidence in your gardening abilities by starting seeds indoors with this foolproof guide.
Time 1 - 2 hours
ComplexityBeginner
Cost$100 (maximum)
Introduction
Learn the essential tips, materials, and techniques for how to start seeds indoors for your most successful vegetable garden yet.
Planting seeds seems basic, and it is. Dirt. Water. Seeds. However, options must be considered, and some knowledge must be applied for guaranteed success and diminished failures in the form of sprouts worthy of going in your yard and maturing to harvest.
Starting seeds indoors has benefits for different reasons. Some vegetables, like tomatoes, peppers, eggplants, broccoli, cauliflower, cabbage, brussels sprouts, kale, lettuce, celery, cucumbers, summer squash, and most herbs, are referred to as “tender plants” because they can’t tolerate cold temperatures. Other vegetables, like artichokes, eggplant, and peppers, require a long growing season and will benefit from being started indoors to maximize harvest time. Overlapping with some of the above, some of these vegetables have slower root development, like peppers, eggplants, cauliflower, and celery. Starting these indoors allows for more growing time and makes them more likely to succeed when they are planted in the vegetable garden.
There are also plants that do not transplant well and are best started in the garden (or outdoors in larger containers). These include cucumbers, melons, pumpkins, and squash. These are all tender, however, so refrain from sowing them outdoors while frost is still a threat.
No matter the reason, most plants and vegetables can only win by being started indoors. Research the specific plant and seeds as you develop your green thumb. Here are the steps for starting your seeds, along with some tips to have a bountiful harvest right in your backyard, perhaps starting in your basement or kitchen window. Cheers to your green thumb!
When to start seeds indoors
I have provided a reference for when to start seeds indoors for some of my favorite vegetables. The following are the times needed for each seed to grow into a transplantable plant for the start of the outdoor growing season.
- Artichokes: 8-10 weeks
- Brussels sprouts: 4-6 weeks
- Eggplant: 8-10 weeks
- Peppers: 8 weeks
- Tomatoes: 6-8 weeks
Tools Required
- Gardening Gloves
- Heating pad
- Indoor grow light
- Permanent marker
- Planting seed tray
- Seed sowing tool
- Small garden shovel
- Spray Bottle
- Watering can
Materials Required
- Compost/vermiculite/coconut coir or seed starting potting soil
- Plant tags
- Seed starting try or starting pods
Project step-by-step (9)
Step 1
Soil to start seeds
Combine one part compost, one part vermiculite, and two parts coconut coir for an easy seed-starting potting mix. It is also acceptable to purchase seed-starting potting soil from a garden center.
Whether you make your own potting soil mixture or purchase some, it is usually fully dry. Add water to hydrate it. This will cause the soil to inflate and make it easier to break apart. Once it becomes soft and pliable, break it up with your hands or a small garden shovel, making sure all of the mix is hydrated and fluffy.
- Tip: Make sure the soil is moist before planting seeds to prevent them from being displaced or sinking too deeply into the soil mix.
Step 2
Transfer the soil mixture
Fill potting trays or two-inch organic pods with the soil mixture. Fill to the top, but don’t compact the soil mix down too tightly. You want the seeds to have room to sprout without a lot of effort or energy spent finding their way.
Tip: Cardboard toilet paper rolls work wonderfully as a potting reservoir because they are organic, allow moisture to pass through, and are small enough to make a seed feel snug.
Step 3
Plant the seeds
Excavate a hole in the center of the potting mix with the handle of your garden shovel or a small seed sowing tool. Be sure to read the specifications for each seed type to determine the depth.
You want your seeds deep enough to be covered and shallow enough to allow the shoot to find its way up and out of the dirt. Some seeds make it easy to determine which side of the seed is up and which is down. If detectable, place the seed so the roots easily grow into the dirt and the sprout easily finds its way up.
Step 4
Label your seeds
Use plant tags and a permanent marker and label your seeds. You may think you will remember which each is, but you may easily get them confused. It is crucial to know which sprouts are which to continue with the ideal light, water and temperature environment for a successful harvest.
Step 5
Mist with water
After planting the seeds, you may lightly mist the soil mixture. Use a gentle spray of water to avoid displacing the seeds. You should also ensure an easy drainage path for the water to drain through the seed trays or pots.
Step 6
Place on a heat mat
Seeds need warmth to grow—between 65 and 70 degrees F is ideal. Heating mats ensure the dirt is at an optimal temperature for growth. For this reason, plants should not be placed in the ground outdoors until the ground temperature is at a level that will allow the seeds to grow and flourish.
Once you have planted the seeds, place them on a heating mat until they sprout and start showing their first leaf, called cotyledons. Once you see these emerge, you can place the tray under light for 12 – 16 hours daily.
Step 7
Introduce a grow light
Once the cotyledons have emerged, you may introduce grow lights. Seedlings need 12 to 16 hours of light daily. Place the grow lights about 4 inches away from the sprouts until they are ready to begin hardening for outdoor transplantation. Make sure the grow lights are not touching the leaves.
Step 8
Start fertilizing
Once the sprouts develop true leaves, start fertilizing until they are ready to be transplanted. Fertilize sprouts every two weeks with ocean water (rich in nutrients) or a balanced fertilizer to encourage good roots and healthy growth. If using a water-soluble fertilizer, it is very important to use it diluted to one-half the normal strength.
Step 9
FAQ
When it comes to starting seeds, what is a blackout period?
A blackout period, mostly used when growing microgreens, is a time when seeds or microgreens are kept in complete darkness to encourage specific growth processes. The length of the blackout period (two to seven days) depends on the variety of microgreens and the desired outcome. The blackout period encourages the development of root systems and longer stems, making the microgreens more tender and flavorful.
What does it mean to sacrifice a seed?
Some seeds, like beans, must be scratched (scarified) and soaked for 24 hours before planting. This will allow moisture to enter the seed and activate germination. This is easily done by scratching the outer layer and placing it in a Ziploc bag with water before putting it in the soil mix.
Why do some seeds (especially flowers) require refrigeration before planting?
Many wildflowers or plants that usually spend the winter buried in the ground getting ready for the spring need to experience cold stratification before planting. To replicate this cold period, this may be done by placing the seeds into the refrigerator or placing the seed packet outside for at least a month.
