Beginning Indoor Seeds: An Introduction

Starting the next season's garden by planting the seeds indoors can be a great way to ensure healthy, productive crops for your vegetable garden. Planting seeds inside can help you have more control over your growing season, expand the varieties available, and reduce your gardening budget.

Caring for the root system before sowing outdoors will prepare your young plants for success before the last frost. By sowing your seeds inside, you will protect your plants from the elements at a young age. As spring rolls in, your vegetables, herbs, or flowers will have strong root systems and be ready to thrive, producing beautiful flowers, fragrant leaves, and healthy vegetables.

Let's take a closer look at the many benefits of planting seeds indoors versus planting them directly outdoors or buying live plants.

Good products on Amazon for starting seeds:

Why should I start seeds indoors?

Starting seeds indoors is well worth the effort. Source: Lorin Nielsen

Setting up an indoor germination station before spring can save you money, give you more control over the plants, and be rewarding.

A seed pack is cheaper than a seedling from the garden center. Materials needed for early sowing can be recycled items like egg cartons or toilet paper, or purchased items that can be reused year after year.

When you start indoors, you have more control over the climate. Schedule lighting by placing seed starts in a south-facing, sunny window or providing additional lighting to mimic sunlight. Control temperatures for germination with a heating mat or place the seedlings in an area of ​​your house that you will keep warm.

For frost-sensitive or semi-hard seeds, they should be started indoors to extend their growing season rather than starting outdoors and waiting for the sprouts to appear after the last frost. Give the plants a little more pampering, allow them to germinate and become stable before putting the seedlings outdoors. Start hardy varieties indoors to give them a good start and extend the growing season, although these can be sown directly outside.

Hardening the plants before permanent placement offers seedlings the best chance of success. It takes time for the plants to reach the right size and strength to transplant outdoors.

Another reason to sow indoors is to grow heirloom plants. Most likely, your local garden center or nursery will not have all varieties of heirloom plants! By ordering from a seed catalog and getting a head start indoors, you improve your garden choices.

You can also grow many species as microgreens. This is a great way to have access to fresh greens in the off-season!

Indoor seed starting media

Different media in large cellsVarious media can be used to start seeding. Source: F. D. Richards

Choose a good soil mix for the seeds. The medium should be loose, have good drainage, and contain some nutrients to get your seeds off the ground. There are also soilless options.

Root rot and steaming can be a big problem for seedlings if they get too wet, so drainage is a priority. The right amount of nutrients is also important. Too much fertilization too early shows up as a growth spurt, but too little root development. Fertilize as soon as the seeds sprout, although some slow release fertilizers are usually included in seed starter mixes.

Don't just dig up soil from your yard to use! Garden dirt can be too clay for the roots to break through and could transmit diseases that could harm your young seedlings. If you only have clay soils, modify it heavily with garden additives like compost.

Use of seed mix or soil

When purchasing a seed starter mix, make sure it is labeled specifically for the seed starter mix. Potting soil is usually only intended for container gardens, while starters are specifically designed for seedlings. These mixtures are intended for seed germination. It is usually fine, loose soils that may contain a slow release fertilizer to give your seeds the best possible germination conditions. They're often a combination of sifted earth, perlite, compost, and peat moss, or a peat substitute like coconut.

Most store-bought mixes are pasteurized or sterilized. Buy a fresh bag of mix, as floors that sit too long can develop fungus, mold, or other problems.

Take precautions by keeping your work areas, tools, and containers as clean as possible to start sterile seeds. Focus on good hygiene in the area and clean your tools and containers between uses. Disinfect containers and tools with a solution of warm water and hydrogen peroxide.

Make your own seed starting mix

To make potting soil for propagation, sift the compost through a sieve after crushing large pieces in your hands. You don't want this ejaculation mixture to be too chunky or heavy. Combine part of sifted compost, part coconut coconut or peat moss and ½ part perlite (a form of volcanic glass). Perlite helps with drainage to ensure your soil containers don't get soaked. The coconut coconut helps it retain moisture when needed. Some people like to add worm castings to this mix to add slow release fertilizer. You can add a portion to this mixture.

Use of coconut coconut or peat moss

Coconut coconut is a peat substitute that has become popular in recent years. It is a processed bowl that is being prepared for planting. Hydrate the bricks, mix them with sand or perlite and use them as a growing medium. In this case, you need to add a liquid fertilizer. You can also use spaghnum peat moss. This is an easy growing medium for seed starting. Both can be used as seed starters on their own, but the addition of compost and perlite will make for better drainage and good nutrition.

Use of vermiculite

You can also sow seeds directly in vermiculite. Vermiculite is a popular medium because the seeds germinate quickly when started with this water-storing mineral indoors. The downside is that they need to be moved into the soil as soon as their first or second leaves appear for nutrients.

Seed start container

Epic 6-cell soil with rootsThe base of the Epic 6 Cell Starter allows for great root growth. Source: Lorin Nielsen

There are many different options for containers. Remember to see what you already own first. You can reuse food containers, packaging or old pots. You can even use a compostable pot that can be planted directly in the ground. Another option is rigid plastic starter containers that you can reuse year after year.

Cell or kindergarten trays

Plastic seed trays are a popular introduction to seed-friendly potting soil. Because of their small, narrow size, they help the seedlings develop a good root system. These are easy to clean and can be reused year after year. These often come with a clear plastic top to increase the humidity.

We like the Epic 6-cell growing trays that we sell in the Epic Gardening Shop. 12 of them fit perfectly in a 1020 tray. They are easy to move around and the large hole on the base allows you to get your takeoffs started with ease. Transplanting is very easy with these!

You can get large plastic sheets with cells that you fill with growth medium and place in a 10 × 20 tray. There are many different sizes that give you a wide choice.

Flat trays

Flat seed trays work well for seeds that you sow in large quantities, like microgreens, or those that you can easily separate like onions. They can also be used to hold blocks from a soil blocker.

Pellets and stoppers

These are a clean and tidy, soilless way to start your seeds. Pellets are small slices of dry growing medium, typically made from peat moss or coconut fiber. Hydrate them and put them in a tray. Plant directly into the moist pellet. Once your seedlings have grown enough, they can be planted directly in the soil.

Root trainers are another type of propagation plug. They open on the side and make transplanting easy! The insides pull the roots down along small depressions.

Fiber mat

These are mainly used for microgreens or germs. Soak the mat to hydrate it, then spread the seeds over it. Keep it moist while growing. For more information, check out one of our in-depth Microgreens guides!

Small pots

These are good for direct seeding or transplanting if you harden them off to go outside. There are many different container options, ranging from the standard plastic or ceramic container types to peat pots, dung pots or coconut coconut.

With peat pots, dung pots, or coconut-coconut pots, they can be planted directly in the garden, making them a good choice for root systems that are difficult to transplant or have delicate roots. Your seedlings will grow well in all of these containers.

Other useful equipment

Peat potsPeat pots and other biodegradable pots can be fully planted. Source: maco_nix

Here are a few other products that could make your gardening work a little smoother!

Heating mats

It has to be warm for the seeds to germinate. If you live in a cold area that is below freezing, it is important to place your sprouts on seedling heating mats. Many plants prefer temperatures of 70 degrees or more to germinate, so these can also be useful in warmer climates.

Grow lights

Many plants need up to 16 hours of light after germination. Hold the lights over the seedling trays to mimic the sunlight. We particularly like T5 fluorescent lights, but many LED lights are also great options for your seedling lighting. If you have a sunny location, you might not need lights, but they are still handy in the winter months! Be careful as some lamps can also give off a lot of heat.

Soil blockers

This is a very useful tool that will allow you to work without a pot. Using pre-moistened media, place the tool on a pile of earth, clamp it together, and then place it in a bowl. This leaves small blocks of growth medium with indentations for planting. When it's time to get out and start gardening, you can transplant these straight into the garden and reduce your reliance on plastic containers.

Manual seeders

Some seeds are tiny and you will need some help planting them in the ground. Hand seeders work really well for gaining more control over the situation.


These will help you drill holes in the ground to start your seeds, although a pencil can also be used. Some are calibrated to help you accurately measure the depth you are planting.

Plant tags

We are all guilty of forgetting what we planted! Use them to mark the date of planting and the variety.


These are a more attractive alternative to plastic covers and create a warm environment for your seedlings and additional protection without sacrificing light.

Mini greenhouse

You can make these with old plastic bottles or milk cartons, or you can buy them. It creates a warm, moist environment for the seedlings to grow. This can speed up the germination time of some plants and can also be used outdoors in cooler seasons to give the seedlings a little more protection.

How to start seeds

DIY newspaper boothsEven DIY pots like these biodegradable, temporary newspaper cells work. Source: library_chic

Let's talk about how to actually sow the seeds! Keep in mind that this can vary depending on the strain you are planting, so always follow the directions on the seed package.

Many seeds require pre-treatment. For example, sweet peas can be soaked overnight, or the seed coat can be incised a little to break them and help them sprout faster. Some seeds only take a few days to appear, while others take two weeks or more. Consult the seed packs for specific instructions.

First, gather your supplies. Either moisten your medium or have water ready. For tiny seeds, wet the medium first so they don't wash away. Larger ones can then be watered. Use a container with drainage holes.

A good rule of thumb is to plant seeds twice their size. When planting, small plants can be a little tricky and a hand seeder can help. You can also dampen a toothpick or fingertip to pick up just one seed for planting.

Usually 2-3 seeds per cell are planted and later thinned out. It's nice to have a few in there in case some don't sprout. Some growers like to plant 2-3 per cell for this reason and also for the ability to keep them together for a bushy plant. For larger cells, place one per cell.

Fill your container with plenty of soil because once you water the soil will be reduced and packed up. When you fill in the soil first, don't grab it too tightly, but rather squeeze it a little to remove air pockets.

Give your seedlings good air circulation. Don't keep your seedlings too wet, but you want to keep the soil moist. One way to see if you need water is to lift your seed tray and feel the weight. When the container feels very light and looks dry, pour water. If it's a little heavy, there is still moisture in it. Don't let your seedlings dry out completely.

Every vegetable or herb has a different germination time. For example, radishes sprout within a few days, while pansies take weeks to show their first leaves. It's nice to have a plant marker with the name of the vegetable or flower and the date it was planted. Consult your seed packets for specific germination times.

Most seeds need to germinate in the dark, so you should have them covered with soil or even a sheet of paper. Let them grow in a dark corner, then bring them out when you see leaves. Some types of seeds require light to germinate, so double-check before planting! Once germinated, plants grow best with light, especially when they are developing their first real leaves.

If many seedlings are close together, thin them out to give them more room to grow. This usually happens just before you move them to their larger pots. Use scissors to trim off the excess seedlings at the bottom line so you don't disturb the roots of the desired shoot.

After the seedling has its real leaves, transplant it into a larger pot to give it room to grow. Don't upgrade them to a giant container, however; Only transplant them to the next size up.

When they're ready to transplant into the garden, begin what is known as hardening. This is when you take your seedlings outside for gradually increasing periods of time. This allows them to get used to the outdoor conditions before transplanting them to their permanent outdoor location.

frequently asked Questions

Pellet potsHydrate coconut pellets and start directly in the coconut medium. Source: vigilant20

Q: Do you need a grow light to start the seeds indoors?

A: Seedlings need 14-16 hours of sunlight, and a sunny window cannot always provide enough. A south-facing window is ideal, but if you start sowing in a cold, dark climate in winter, you will need a grow light to ensure the best growth. Without the right amount of light, the seedlings will become leggy or will not develop well.

Q: Can all seeds be started indoors?

A: Some seeds can benefit from being sown directly outdoors and you don't have to bother sowing them indoors early. Timing is important here. If you have a short growing season, it is helpful to plant plants indoors in the heat of your home or greenhouse to give them a head start. Review the best practices for your climate or zone.

The green fingers behind this article:

Leave a comment