The night temperatures are still below freezing. The trees are still bare. Winter coats are still in arm’s reach on the way out the door. Yet there’s something in the air that says spring is on its way. A couple weeks ago, I shared my 5 Step Garden Plan for the Spring Growing Season. Now, it’s time to set that plan into action … at least indoors. Indoor seed starting is a pivotal part of making the most out of your spring and summer garden. Indeed, many stores are already offering displays of seeds, soil, fertilizer, grow lights, and seed starting trays. It can be difficult to know exactly what we need to get started.

Many of us are taught from a very young age that there’s nothing to starting seeds. All we need is some soil in a cup, a seed, some water, a little sunlight, and a wait-and-see attitude. That may be sufficient to entice children and beginner gardeners to the art and science of gardening. But there’s more you can – and should – consider. Performing certain tasks now can prevent future problems and give your young seedlings the best possible beginning. Take care of your plants now at the start, and they’ll return the love ten fold later this season.

Containers and Seed Trays to Start Plants

If you’re planting a lot of seeds or many kinds of seeds, you’ll need containers to start the germination process. Small pots or seed trays can be your best friend.

There are many kinds of seed starter containers on the market and many are reasonably priced. But which kind is best? Through experience and practice, there’s a few things I look for when I’m purchasing containers for seed starting.

Limit Plastics Where You Can

I am constantly working to limit plastics in my gardening. It’s a work in progress to be sure, and the current offerings on the market don’t make this goal easy since most are made of plastic. If you have to use plastics, make sure the plastic is marked as recyclable, or it’s sturdy enough that you can use it more than once.

For small gardens, stand alone peat pots are great. Peat pots have great drainage, allowing oxygen to pass freely to the soil in ways that plastic doesn’t.

If you’re planting lots of seeds, You have a few options open to you. One method rising in popularity is soil blocking. soil blocking is great for starting lots of plants at once. Plus, unlike seed trays, which we’ll talk about in a minute, your plants won’t be confined to one small area. [Check out this link if you want to know more about soil blocking.]

The other option is, of course, seed trays, which most gardeners are familiar with. Seed trays have individual compartments in rows for starting a whole garden of seeds in one small space. With seed trays, it’s easy to know which seed you planted where. Plus, seed trays won’t take up all of what may be the only coveted sunny window in your living space. You may have to settle for some plastic if you’re using seed trays. Use trays with refillable peat containers that you can use year after year. These allow good drainage and oxygen for your plants, but take up less space than individual peat pots.

Pellet Seed Trays vs Cell Seed Trays

Avoid seed starter trays that come with pre-measured peat pellets that expand when you add water. These trays are advertised to make seed starting easy, but in the long run, they’re anything but. The coir fibers (derived from the coconut husk) can hinder your fragile seedlings’ brand new roots as they grow. If your seedlings have to work too hard too early in their lives, their growth will be stunted. Your seedlings need room to grow a good root base.

Some manufacturers recommend that you cut away the webbing from the peat pellets to lessen the danger of root binding. This helps some, but undoes a lot of the “ease” that brands advertise for this variety of seed tray. In the long run, it’s better to avoid these types of trays outright.

Cell seed trays offer compartments for you to fill with soil and plant your seeds. Like pellet seed trays, these cells are individual, miniature pots to house your seedlings while they’re small. Unlike pellet seed trays, there’s more room in the cells than the pellets provide. This gives your young plants room to expand a little further.

Heating Mats vs Greenhouses

Seeds are quicker to germinate if they feel a little heat around them. Soil warmed from sunlight naturally encourages seed growth. In the colder early spring weeks, this heat can be simulated through the use of mini-greenhouses or heating mats. Both will provide your seeds with warmth to trick them into sprouting early, but in most cases, simpler is better.

Heating mats can cost you as much as $70 USD, but it’s not necessary to pay that much. Indoor seed starting can be as simple as placing your soil in a sunlit window. The ambient room-temperature air, already warmer than the outdoors, will warm the soil without you having to do anything special. Seed trays are often colored black to absorb the sun’s infrared rays and deliver that heat to the soil.

Many seed trays on the market will also come with a clear cover. When placed over the seed tray, this lid allows sunlight in, trapping the resulting heat to warm your gestating seeds. There is a drawback with this: seedlings may grow to the top of the greenhouse before they’re ready to be transplanted. Once your young plants are tall enough, you may need to prop up the cover, or remove it altogether, until your seedlings are ready to transplant.

How Much Light Do You Need To Start Seeds?

Speaking of sunlight, seeds need lots of light to germinate. In the Northern Hemisphere, a southern-facing window is always best to start seeds. South-facing windows receive more light than a north-facing window (this is opposite for the Southern Hemisphere, of course). Depending on the way your living area is laid out, you may not have a sunny window to start seeds. Fear not! Seedlings don’t need direct sunlight to germinate. And a grow light can supplement the amount of natural light your seeds receive.

How much light do seedlings need? Follow the sun’s guidance. Turn the grow lamp on at least an hour before the sun rises and off an hour after the sun sets. This is particularly important for plants that will ultimately live their lives outdoors. An even circadian rhythm will allow the plants to quickly step into a natural rhythm once they’re transplanted. The extra time before sunrise and after sunset also gives your plants at least 12 hours of sunlight a day. This subtly tricks your seedlings into thinking it’s later in the year than it truly is. Time to rise and shine!

Kinds of Grow Lights for Seedlings

There are many kinds of grow lamps on the market with many kinds of lighting. LED grow lights are the current top of their class for many reasons. LED lights are cheaper on your home electric bill than other lights. They come in multiple light spectrums, each of which serves your plants differently.

Blue Spectrum Light offers the best light spectrum for seedlings and young plants. Blue spectrum light causes plants to open their pores wider and take in more CO2. This helps seedlings create strong roots and stems and reduces “leggy” plants (read more about leggy plants below). Red Spectrum light is extremely easy for plants to absorb and encourages photosynthesis. Red light is most useful with slightly older plants who have more leaves. It helps trigger chlorophyl which encourages leaves, fruit, and to a lesser extent, stems.

In most cases, grow lamps tend to combine these spectrums into a single lamp.

How Far Away Should A Grow Light Be For Seed Starting?

You want to make sure you’re not depriving your young plants of light when they need it most. Generally, grow lights should be about 12 to 20 inches from the soil. This goes for natural sunlight as well as artificial light from grow lamps. Seed starting trays and pots should be as near a window as possible without exposing them to potentially cold window panes.

If the light is too far from your soil, your seedlings have to stretch to reach the light they need. Seedlings with long, thin stems are commonly called “Leggy,” and it can really hurt (even kill) your tender young plants. Leggy seedlings are prone to all sorts of problems, including dampening off (more on that in the next section). Strong seedlings have robust stems that keep them upright. Strong stems allow seedlings to withstand a reasonable amount of wind and rain (and watering from the watering can).

How Much Water do Seeds Need to Start?

Seedlings don’t need near as much water as adult plants. In fact, one of the most common problems beginners face when starting seeds indoors is overwatering. When starting seeds, your soil should be wet but not damp, and certainly not sopping! Overwatering young plants can cause a whole host of problems that you want to avoid.

Some seed starting trays have clever ways to prevent damage to young plants from overwatering. A tray may have a reservoir below the seed tray to allow watering from below. Watering your seedlings from below is ideal as it keeps the top of the soil dry. If you have to water from above, keep the watering lighter so it can soak into the lower layers. Take care not to drench the soil. Mold has a tendency to grow along the top of soil and seedlings are most vulnerable there.

Damping Off. What Is It? How To Stop It?

Seedlings growing in soil that is too damp may develop a condition called damping off. Damping off is a fungal disease that often affects seedlings who are more vulnerable than adult plants. Damping off is fatal to seedlings. The stem rots at the soil layer and deprives young plants of nutrients which ultimately kills them. Once damping off occurs, the affected seedling dies. There is no cure for affected plants, but there are methods to preventing damping off from occurring.

Since damping off is caused by fungus, the simplest way to prevent it is to treat the soil. Cinnamon is a natural anti-fungal agent and will help to repel damping off. Sprinkle a light dusting of cinnamon on the top of the soil for a natural way to stave off the fungus that causes damping off. (For more information on this phenomenon, check out the post all about White Mold.) Your seedlings will thank you.

Soil Starters

There are lots of different kinds of soil on the market. It can be confusing to know what you need when you’re starting your seeds. Keep in mind that seedlings appreciate a much lighter soil than mature plants. In fact, seed starting “soil” is a misnomer. A mix of peat moss, perlite, vermiculite, coconut coir, sand, worm castings, and other light ingredients make up seed starting mixes. This mix is lightweight and drains easily. Well-drained soil prevents a lot of problems young plants may encounter, like the aforementioned damping off. A seed starting mix allows tiny seedling roots form more quickly and provides the nutrients they need from the start.

You can use conventional potting soil to start your seeds if you’re careful about not overwatering your seedlings. Potting soil is light enough and contains a moderate amount of the nutrients young seedlings need. However, never use garden soil to start your seeds. Garden soil is often not screened for weeds and rocks and it’s extremely heavy. Seeds starting in garden soil will have a difficult start to life as they try to burrow into the compact soil. They may become stunted as a result.

Recapping: What You Need When Starting Seeds For Spring Planting

That’s all there is to it! Now you can adopt that wait-and-see attitude you were encouraged to have when planting seeds as a child. Soon enough, your seedlings will emerge into the world with a bright future ahead of them!

What’s Next?

Once your seedlings emerge into the world, there’s a whole host of things you may want to think about – Especially if you’re container gardening. Check out this post about Beginner Container Gardening: You Are Your Plants’ Whole World.

You may also want to consider how you’re going to transplant these seedlings once they’re ready to leave the seed trays. Don’t worry, we’ve got you covered there too!