Whether you want to create an indoor garden, or simply give your outdoor plantings a head start, growing your seeds indoors is a fantastic way to make sure your plants and vegetables grow strong and healthy.
When you start seeds inside, your plants can grow earlier and more vigorous, protected from late frosts and unpredictable weather.
Starting seeds indoors is simple and reliable, and here’s how to do it.
Equipment for Starting Seeds Indoors
Here is the equipment you will need to start seeds indoors.
It goes without saying that you will need seeds. Choose seeds from a reputable company, and look for a date to make sure they are fresh.
Seeds are best nurtured in small pots that will help them get strong and robust before being transplanted outdoors or into a larger pot.
You will need a potting mix specifically for seedlings, because regular potting soil is not usually fine enough for delicate, early roots. You can choose to purchase a pre-made seedling mix, or purchase peat, pearlite, and vermiculite to make your own.
TIP: You may also choose to get seedling cups which combine the soil and small pots into a single system that simplifies seed-starting and transplanting.
You may also need:
A Grow Light
Most seedlings need 6-8 hours of direct sunlight every day in order to thrive. If you don’t have adequate sunlight indoors, your plants may need a grow light.
A Heat Mat
Seeds germinate best with warm, consistent temperatures. If your home has cold drafts or air currents, or inconsistent temperature, a heat mat can help provide the seedlings with the constant temperature they need to root best.
A Plant Mister
Seedlings need to remain consistently moist, and because they are so small, even a dry millimeter or two at the top of the soil can dry out your new plants. Using a watering can to pour water on them can pour water with too much force, dislodging new delicate roots. A plant mister is the best way to keep seedlings consistently and gently moist.
A dome for humidity. Providing a tiny greenhouse environment is another crucial step in keeping seedlings moist and preventing them from drying out. You can use a seedling dome with a transparent lid to create a humid environment, or create your own with plastic film with a few holes poked in it.
The fact is, seedlings end up looking a lot alike, and no matter how careful you are, it’s easy to forget what you planted where. You can purchase plant labels or make your own, but it’s always a good idea to label your seedlings.
How to Start Seeds Indoors
Step 1: Start Your Seeds at the Right Time
While starting seeds indoors help you prolong the growing season and get earlier harvests, you shouldn’t start seeds too soon.
Most vegetables should be started indoors, six weeks before the last frost date, but specific planting information will be listed on the seed packet.
You should look up the last frost date in your region, and use that to determine when to start your seeds. Here are some general guidelines of when to start growing popular vegetables and herbs:
- 8-10 weeks before last spring frost: peppers, thyme
- 6-8 weeks before last spring frost: broccoli, brussels sprouts, cabbage, cauliflower, celery, tomatoes, basil, oregano, parsley
- 4-6 weeks before last spring frost: lettuce, sage, chives
- 2-4 weeks before last spring frost: cucumber, melons, pumpkins, squash
Step 2: Prepare Your Planting Area
Read the packaging that comes with your seeds. Depending on the kind of plant you are growing, you may need to soak or chill seeds before planting. There will also be specific guidelines for the plants you want to grow which are more relevant than the general guidelines we are giving in this article.
Look for a warm area in your home with low light to start your seedlings. In most cases, seeds want a warm, moist, dim place to germinate, and then a sunny place to grow.
In many homes, the top of the refrigerator is a great spot, because the refrigerator creates constant low heat.
An oven or heat register is typically too warm, as is a human heating pad or electric blanket.
Step 3: Plant Your Seeds
Fill clean containers with your seedling potting mix and moisten the soil.
Some pre-made seedling pods need to be soaked in water before use, so you may need to follow the manufacturer’s instructions.
Use a water can or mister to moisten the soil.
Look at your seeds
Some plants have tiny seeds that almost float like dust, while some have larger, round seeds that are easy to handle and count. You generally want to plant 2-4 seeds per seedling pot, but some plants make that easier to do than others. For tiny seeds, just plant a few, and gently handling them with tweezers may help. For larger seeds, choose to plant the biggest ones, which are often the healthiest.
Plant your seeds at the right depth
The seed packet will tell you how deep to plant the seeds. In most cases, you can simply use the tip of your finger or a pencil eraser to gently press seeds into the soil.
Label your containers
Label each container with the name of what you planted. In many cases, you will also want to keep the seed packaging, because it contains instructions on thinning and transplanting.
Cover your seedling containers
Use a dome or plastic film that will retain humidity, but poke holes in it for some ventilation.
Step 4: Maintain Your Seeds
Mist them with water 2-3 times a day.
The actual frequency of misting will depend on the humidity level and how moist your seeds are, but misting will keep them damp and give you a chance to see if they are growing.
Watch for germination
In most cases, you will see the first tiny leaves appear within 1-2 weeks.
Move them to a higher light location or add a grow light
Once you see leaves, your plants are ready for light.
Move them to a sunny window or turn on a grow light
If they are in a window, rotate them regularly so they get light on all sides.
Step 5: Transplant Your Seedlings
When your seedlings have developed their second set of true leaves, or they are 2-3 inches tall, they are almost ready to transplant.
If you are transplanting your seedlings outdoors, it’s important to make sure that your last frost date has passed, and check your seed instructions for the optimal outdoor temperatures for your seedlings.
Starting about 10 days before you move them outside, harden them to outdoor conditions by setting them outdoors in filtered light in a wind-sheltered spot for several hours a day, gradually increasing their exposure to more daylight and cooler evening temperatures before moving them outside full-time.
Plant them with their plant labels at the distance recommended on the seed packaging.
If you are keeping your seedlings indoors, as part of an indoor garden, you may need to thin your seedlings by removing the 1-2 weakest seedlings from each seed pod, then moving the biggest and strongest ones into larger pots where they will grow.
Growing your own plants from seeds started indoors is a great way to save money on buying produce, and is also incredibly rewarding.
Kids will find it fascinating and educational, and somehow everything tastes better when you grow it yourself.