Skip to main content

Gardening 101: Making sure your seedlings grow into healthy plants

Gardening is a relaxing hobby and a great way to brighten your yard. If you aren’t sure how often to water seedlings or when you should transplant them, then these questions can take some of the relaxation out of gardening. There are a few ways to grow plants, from sowing the seeds directly in your garden to buying an already-mature plant. Arguably the most popular way, though, is to start your seeds indoors.

The beginning is easy, but what happens when they start sprouting? Whether you’re just starting your garden or trying out a new way of gardening, here is everything you need to know about taking care of seedlings.

A small collard seedling being watered with a red watering can

How often to water seedlings

Seedlings aren’t able to store water for very long, so they need soil that is constantly moist. This means watering them a few times a day, depending on how quickly they dry out. Test your seedling’s soil with the end of a finger to about an inch deep. If the soil is dry, your seedling needs water. If the soil is soggy, your seedling has been overwatered. If your seedlings have already sprouted, pay attention to their color. Yellow seedlings are seedlings that have been overwatered, while seedlings that are limp and pale may be underwatered.


Yellowish seedlings leaning over

How to keep seedlings alive

Aside from water, the most important thing for your seedlings is sunlight. Seedlings need roughly 10 hours of light a day, so finding the sunniest part of your house is important. You may need to supplement with artificial light, depending on where you live, but there are a lot of products available on the market, for a range of prices, so you can light your plants on a budget.

If your plants are getting leggy or growing sideways, this is a sign that they either aren’t getting enough sun or the light is hitting them at an odd angle. Plants move toward the sun, so the best way to get nice, even growth is to position the light above them.

When you plant your seeds, you should add a humidity dome made of plastic over the trays. This creates a mini greenhouse for your seeds, which you can remove when they sprout.

Container tips

The trays should be wide and flat containers to give the roots (when they begin to grow) enough space to avoid overcrowding. Another container tip for keeping your seedling alive is to use plastic rather than clay or another material when you’re starting seedlings, as plastic retains moisture more consistently.

A tray of pepper seedlings in biodegradable pots

What should you do once seedlings sprout?

Once your seedlings sprout, you can slowly remove the humidity dome. Open a few ventilation holes in the dome, so the sprouts aren’t shocked by a sudden change in air temperature and humidity.

Continue checking on the soil’s water content. Growing plants need a lot of water to fuel their growth, which means they’ll be absorbing water more quickly. The soil will dry out faster, so you’ll need to water more frequently or begin bottom watering.

Bottom watering means pouring the water into a dish or tray on which the seedling’s individual containers sit. This allows the plants to absorb water through their roots at a more even rate. If you bottom-water your seedlings, only add enough water to cover the holes in the bottom of the seedling container. Remove any water that’s left standing for more than half an hour to avoid an increased risk of diseases, pests, and root rot, and to keep the water fresh.

If your seedlings have sprouted and there is more than one in each cell, you’ll need to thin them. Multiple seedlings in a single cell compete for resources, which often results in both seedlings dying or being severely weakened. Once your sprouts have grown a few sets of leaves, choose the strongest seedling in each cell and leave them. Gently pinch the seedlings you need to cull and pull steadily up. The roots will likely come with it, but if they don’t, don’t worry about it too much.

Six seedlings in a tray

How long can seedlings stay in trays?

Seedlings are ready to move out of the trays when they are twice as tall as the tray they’re in. Once they reach that height, you have a couple of weeks of wiggle room to prepare a pot or start hardening them.

Hardening is a crucial step if your sprouts are going to be outside in your garden. It helps your plants adjust to their new environment, giving them a greater likelihood of survival. When the temperature outside consistently reaches 50 degrees Fahrenheit or more, start leaving your sprouts outside for 3 or 4 hours every day.

You should pick a spot that is shaded and protected from the elements, then gradually move them into the sun. When the nights are consistently above 45 degrees Fahrenheit, your sprouts can stay outdoors overnight.

Person transplanting a cucumber seedling into a garden

When should you plant the spouts?

Now you’re ready to plant your sprouts. Planting should occur in spring, although the exact time depends on the type of plant you have. A cold-weather plant, like most leafy vegetables, can be planted about two weeks before the last frost, while warm-weather plants, like most flowers, shouldn’t be planted until after the last frost of the season. Water your plants in, and you’re done!

Now you know all the potential pitfalls of raising seedlings, and you’re prepared for what may come! Watching the little green shoots poke out of the soil is exciting, and successfully transplanting your seedlings is incredibly satisfying. So enjoy your gardening experience!

Meanwhile, if you’re looking for more, take a look at our tips for growing houseplants from seeds.

Editors' Recommendations

Cayla Leonard
Cayla Leonard is a writer from North Carolina who is passionate about plants.  She enjoys reading and writing fiction and…
6 tips you should keep in mind when building your own drought-tolerant garden
Build a drought-tolerant garden to save water and money
Border garden planted with drought-tolerant flowers

Watering can be a grueling chore during the summer, and it’s no secret that your water bill can skyrocket if you have to tend to a lawn. Enter drought-tolerant gardening, also known as xeriscaping or water-smart gardening. The driving concept behind this gardening approach is simple: Create a plant space that thrives without too much water.

Designing a drought-tolerant garden is rewarding, but it can be difficult to begin. There's an upfront cost of time, energy, and money to consider. In addition to new, drought-tolerant plants, you may also need to get mulch, rocks, and tubes for an efficient watering system, and setting everything up can take a lot of time and effort. In the long run, though, your low-maintenance garden will be well worth it. You’ll have a garden that's friendlier for the environment and your budget!

Read more
Grow your indoor or outdoor garden and support these Black-owned plant shops for Black History Month
Get your next leafy friend from one of these Black-owned companies
Various plants on different stands

If you're a plant parent, you buy your supplies and new baby plants from somewhere. So, instead of the chain stores, consider supporting Black-owned plant shops to get your leafy friends everything they need to thrive. Check out any of these Black-owned companies to find your next plant addition no matter where you are, because every one of these businesses ships all over the U.S.

Grounded
Mignon Hemsley and Danuelle Doswell started this beautiful plant company in 2020 to help create a calmer space in homes through the addition of greenery. If you have no idea where to start, Grounded offers complimentary 15-minute consultations to get you going. It has a subscription option for the more adventurous plant parent, and if you have fur babies at home, look at their pet-safe options so you won't have to worry about a curious nose.
Crazy Plant Bae
From plants to planters to a subscription box, Crazy Plant Bae has a little of everything. No matter how green your thumb is, you'll find something to fit your budget and space. Get the kids involved in gardening and sign them up for one of the workshops, or have them visit your child in their classroom. But the best part about this company is that it's a Black women-run business with its third generation of family members, and it has over 40 years of service at your disposal.
deVINE Plantery
If you want easy-to-care-for plants without a lot of fuss, or more unique plants, check out deVINE Plantery. This Black woman-owned company has adorable plants, fun accessories, stunning art pieces, and a few other gift ideas. Need help styling the plants in your home, want a consultation about what plants to get, or want to take a gardening class? This business offers all of that and more.
De La Fleur Designs
If you want only flowers for your space with a lot of color and beauty, then De La Fleur Designs is where you should look. It doesn't just put together any ordinary bouquet. Owner Daphne oozes the sophistication and elegance you'll see in whichever arrangement you choose. Whether you need a sympathy arrangement, wedding flowers, or want to sign yourself up for a monthly bouquet delivery subscription, De La Fleur will take care of it all.
The Plant Project
The first Black woman-owned plant company in Texas, The Plant Project opened its doors in 2020 to bring the joy of all things leafy to the area. Plants with a pop of color, herbs, plant accessories, and even a plant self-care set are all on the menu. Or visit one of its four locations to get the full in-person experience of a plant shop and see how amazingly beautiful the inside of its stores are.

Read more
Gardening 101: 7 easy seeds to grow in cups for a tiny, adorable, and low-maintenance indoor garden
How to choose seeds to start inside of cups
Seed starting in cups

Many gardeners start seeds indoors during the last weeks of winter or early spring to get a head start on the growing season. When it's too cold to plant anything outside, you can start seeds indoors and transplant them in the ground once the weather warms up.

So what can you use for your seeds without spending a fortune on seed-starting trays? Plastic cups left over from parties or camping trips are ideal. Recycling these cups provides the perfect temporary (or even permanent) homes for your plants, and you'll get the cutest container garden in the process!

Read more