How to Start Seeds Indoors (Everything You Need to Know to Get Started)

How to Start Seeds Indoors (Everything You Need to Know to Get Started)

There are a couple of different reasons you might want to start seeds indoors. You may be trying to get a jump on the growing season and plan to later move your plants outdoors. Or you may be adding new plants to your indoor garden and would prefer to grow them yourself from seeds. If you’re keeping your plants indoors year-round you aren’t subjected quite as much to the plant’s grow cycles. With the right lighting or grow lights, you can start your seeds anytime and grow perfect plants in any season. 

Growing from seeds is usually the best option when you’re growing many plants. With seeds, you don’t have to pay for plants individually. On the other hand, you may just want to ensure the little seedling is raised the way you want. It’s so much fun to start seeds indoors and watch them grow into healthy, beautiful plants. You don’t really need a specific reason to start some seeds.

Starting seeds indoors for your outdoor garden can take a little more careful timing than plants that remain indoors. Plants have different ideal start dates. Generally, it’s best to start your seeds about 6 weeks before the first frost in your area. This will give them plenty of time to develop into healthy seedlings. Then you can safely transport them out into the world for the spring and summer months. Be aware of what temperatures your plants can tolerate when moved outside. This can vary quite a bit for plants that are sensitive to the cold.

Where to Buy Seeds

You can purchase seeds from any local gardening store, home improvement store, or even grocery stores with a gardening section. If you’re pickier about your seeds, request a seed catalog from several garden companies to compare prices and products. The Old Farmer’s Almanac provides an excellent list of companies that provide free seed catalogs.

Of course, you can always search seeds on Amazon, if you prefer to shop from the comfort of your home and have them conveniently delivered to you. 


Now That You Have Seeds

Seeds are obviously necessary. Once you pick out your seeds, be sure you purchase and plant enough to prepare for some losses. Some seeds may not germinate, and some might die in their early stages of life. The number of seeds that germinate depends largely on seed quality and type of plant. Some plants are a little trickier than others, and their seeds may be more stubborn.

Containers to Start Seeds Indoors

You’ll need clean, sterile containers for your seeds. You can purchase containers, such as peat pots or plastic trays, online. This won’t be your plant’s permanent home. Therefore, if you want to save money, consider using the compartments in an egg carton with the lid cut off. Make sure your container has drainage holes in the bottom, so your seeds and seedlings don’t drown. If you’re growing more than one type of plant, labels are helpful to remind you of what’s what.

Potting Mix

Seeds and seedlings require a slightly more specific potting mix than your typical indoor houseplant. Because the roots are so new and delicate, choose a potting soil or starting mix that is light and fine. This will allow the roots to maneuver more easily. You don’t need to worry about nutrient-rich soil or fertilizer for your seeds. The seed itself should have all the nutrition it needs to get to the seedling stage. Once the seedlings have grown their first true leaves, you can transplant them to a potting mix with more nutrients.

Light and Warmth

Some seeds require light to germinate, while others don’t. Some should be pressed only lightly into the soil to receive some light, while others should be buried deeper. When you purchase your seeds, the package should indicate the lighting requirements and soil depth for your plant.

While seeds may not be affected by light, warm soil can often help them germinate. You can place a heating mat under your trays to encourage germination. Alternatively, try placing them on a warm surface, such as the top of your refrigerator. Remove seeds from their heat source once they have germinated. The newly developed seedlings may grow too fast and become leggy if left in warm soil.

Once the seeds have sprouted, they will require some light. You can place them near a sunny window but be sure they won’t be exposed to chilly temperatures overnight. For the best results you can purchase an adjustable grow light. Once the seedlings appear, position the light about 1-2 inches above the tallest seedling. Adjust it higher as they grow. If you’re starting seeds in the winter, or you don’t have much natural light available, a grow light can help. If your seedlings start getting long and leggy, they are likely not receiving enough light.

Water Tips to Start Seeds Indoors

Water your seeds carefully and delicately, so the seeds and soil are disturbed as little as possible. You can do this with a mister to allow only small amounts of water to be added at a time. The soil should remain fairly moist without becoming overly soggy. Covering your trays with a plastic lid or a layer of plastic wrap can help retain warmth and moisture. Just be sure the plastic has holes to allow for some ventilation.

Tips For Planting and Transplanting after you start seeds indoors

Placing Seeds into the Soil

The first step is to place your seeds into the soil, per the directions included with your seeds. Different plants have different preferences for soil depth, but this is usually indicated when purchasing seeds. Some need to be pressed deep into the soil, while others require a light sprinkling of soil to keep them in place.


Always use clean containers and sterilized soil to ensure there is no fungus or bacteria present in your potting mix. A lack of sterility can lead to mold and fungus problems. This can be harmful to your new plants when they’re just starting out.


As mentioned earlier, water carefully and keep your seeds moist and warm. Cover the seeds trays with plastic to create a more humid environment. Once your seeds have sprouted, remove any plastic covering you were using. Then move them into a bright, sunny location or place them under a grow light.

First Transplanting

When their second pair of leaves (or “true leaves”) appear, transplant the seedlings into new pots and provide them with a heavier, more nutrient-rich potting mix. Water your seedlings well at this point. And keep them out of direct sunlight for a few days, while they become established in their new homes. 

If your plants will remain indoors, your work is mostly done. You just need to care for your plant as it continues to grow. If your plants are going outdoors, there are still a few important steps to prepare them for the outside world.

Hardening Off

Plants headed for your outdoor garden need to undergo a “hardening off” period. Do this by incrementally increasing their exposure to the elements outside. You can start by placing them in a partially shaded area that is safe from any wind or hot sun. You should also start watering them a little less. Every day, you can increase their wind and sun exposure until they’re eventually ready to be placed in the ground. This period usually ranges from about 7 to 10 days.

Second Transplanting

Once your plants have grown more familiar with the outside world, it’s time to place them in the ground. Transplant them into loose, aerated soil so their roots can easily penetrate the earth and they can become safely established. Give them plenty of water after transplanting and your new plants should be ready to grow into healthy adults.

Now You Know How to Start Seeds Indoors

Growing your plants from seeds is a little more complicated than caring for a houseplant or an outdoor garden. The seeds and seedlings are more delicate that an established plant and they’re much more sensitive to their environment. However, with the proper care and attention, it’s not too difficult to raise your own plants from seed. Just be prepared that some of your seeds may not germinate. And some species are a little more stubborn than others.


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