How to Water Seedlings

Water is vital for growing plants. Determining how much or how little to give your growing plants can take time and effort. Too little moisture stunts growth and causes seeds to fail. On the other hand, overwatering can drown or rot plants.

This guide to how to water seedlings is designed to take you through the entire process, explaining how to keep your seedlings happy and hydrated.

1 How to water seedlings
Learning how to water seedlings is a key part of the growing process.  

Growing From Seed

If you are starting your plants from seed, you can either start them undercover and transplant them after germination or sow them directly into your garden.

Starting indoors has a number of benefits. It enables you to start sowing earlier in the spring. This is helpful if you only have a short growing season. It also allows you to protect the young seedlings from pests.

Another advantage of starting seeds undercover is that you can better control the growing conditions such as temperature, moisture levels and light levels. Creating the ideal growing conditions helps to improve germination rates and produces stronger, healthier plants.

The following plants can all be started under cover and transplanted into your garden after germination:

  • Broccoli,
  • Brussels Sprouts,
  • Cabbage,
  • Cauliflower,
  • Celery,
  • Eggplant,
  • Kale,
  • Leek,
  • Lettuce,
  • Onion,
  • Okra,
  • Pepper,
  • Sweet Potato,
  • Tomatoes.

2 Start seeds undercover
Learn how to start tomato seeds undercover.

The following crops can be started indoors but are prone to transplant shock or dislike having their roots disturbed. This can cause them to fail. Sensitive plants include:

  • Celery,
  • Chard,
  • Cucumber,
  • Melon,
  • Peas,
  • Pumpkin,
  • Spinach,
  • Squash.

I like to start sensitive plants undercover in biodegradable pots. Once they are large enough to go in the garden, they can be planted still in their pots. The pots break down as the plants grow. This avoids handling the root system and upsetting the plants.

Finally, some crops, such as root crops, are best sown direct into their final growing position. The following should be started in their final growing position:

  • Beans,
  • Beets,
  • Carrots,
  • Corn.

3 Sow seeds direct
Some seeds are best sown directly into their growing position.

Germinating Seeds

There are two ways to germinate seeds. Either:

  • Place the seeds in the center of a moist paper towel and put them in a sunlit window,
  • Sow in a seed starter tray roughly 1 inch deep or on the surface and lightly moisten the soil.

Whichever method you choose, it is essential not to let the seeds sit in water.

If you are using the paper towel method, it should be moist, not soaked.

If you choose to use a seed starter tray, moisten the soil and allow it to dry out a little bit before sowing the seeds. Your tray should have drainage holes in the bottom. This encourages excess moisture to drain away. While moisture is vital, allowing your seeds or seedlings to become too wet can cause rot or disease.

A seed-starting capillary system or capillary mat can be used to keep your seeds hydrated. Along with watering from below, this method is kinder to seeds and delicate young plants than watering from above.

Place the seed trays in a propagator or cover them with a piece of plastic to improve germination rates. Remember to remove the cover regularly to air the seeds and prevent mold.

As the seeds start to germinate, aim to keep the soil evenly moist.

If you want more information on how to successfully germinate seeds, our detailed guide is packed with useful tips.

4 Water seedlings for germination

Even moisture levels are key to successful germination.

Continue to grow your young plants on under cover until they have produced a couple of pairs of true leaves and the outside temperatures have warmed sufficiently. Then harden your plants off before transplanting them into the garden.

Keep a careful eye on your plants when hardening off and in the few weeks after transplanting. Exposure to the sun and spring winds can quickly dry out the soil around your plants. When hardening off, place your plants in a spot that is sheltered from the wind.

Transplanting Seedlings

Water your young plants well before and after transplanting. This helps to prevent transplant stress.

Avoid transplanting your seedlings during the hottest or sunniest part of the day. Transplanting in the morning or late afternoon, when it is cooler, helps to reduce moisture loss and heat stress.

After transplanting, mulch the soil around the seedlings.

Regularly check your plants in the weeks after transplanting, watering the soil when necessary. Maintaining even soil moisture around your plants helps them to settle more quickly into their new home.

5 Water evenly after transplanting
Keep the soil evenly moist after transplanting.

How Often to Water Seeds

Seeds grow best when the soil is consistently moist. Because most seeds are sown shallowly, they initially only develop short roots. Keeping the top layer of soil damp is vital to the success of these seeds.

Be careful not to overwater your seeds. Too much moisture can wash away or drown seeds. It also encourages mold, fungi, algae or rot. These issues can be avoided by planting to the recommended depth.

Allow the soil to dry out between waterings.

Remember, plants and seeds in shady areas require less moisture than those growing in sunnier spots. When watering your seeds, use a plant mister.

If you are soaking your seeds before sowing them, don’t soak the seeds for more than 24 hours. While soaking can help soften the shell, too much moisture means the seeds won’t germinate. Large and wrinkled seeds, as well as those with a hard coat, benefit from soaking before planting.

The following seeds benefit from soaking before planting:

  • Beans,
  • Corn,
  • Lupine,
  • Nasturtium,
  • Peas,
  • Pumpkins,
  • Squash,
  • Sunflowers,
  • Sweet Peas.

While you wait for your seeds to germinate, keep the soil damp but not wet. Moisten the soil lightly, no more than once a day.

If you are starting the seeds in a propagator or covered seed starter tray, the soil may stay moist for longer. Check your seeds every day to see if they need a drink.

Growers in warmer climates may find themselves watering every day or even twice a day.

Don’t allow the soil to dry out.

How to Water Seedlings

Ideally, you should be watering your seedlings every 1 to 2 days. Exactly how often depends on a number of factors, including:

  • Temperature,
  • Soil type,
  • Tray size.

Young plants grow best with a consistent, even supply of water. The soil should be neither dry nor soggy.

If your plants are on a heat mat or beneath grow lights, you may need to water them more frequently. Both of these gadgets, while helpful, can raise the temperature around your seeds, causing the soil to dry out.

Water seedlings when the top ½ inch of soil is dry.

If you are unsure, touch the soil. If it feels dry, it is time to water. Dry trays and pots also feel lighter than ones holding lots of water.

Another way to work out if your plants need a drink is to look at them. As they dry out, plants lose their plumpness. The color may also fade or the leaves start to droop.

In general, plants growing in pots either inside or in a greenhouse require more frequent watering than those in the ground. This is because the soil in pots is shallower and has less room to store moisture than in a deep garden bed. Outside plants also benefit from the early morning dew.

6 Water seedlings outside
Seedlings growing outside benefit from the morning dew.  

As they get older, seedlings become more resilient. After a few weeks, you can reduce watering to every other day. Eventually, you need only water deeply once or twice a week.

There are 2 ways to water seedlings:

  • bottom watering,
  • top watering.

Both have their advantages and disadvantages. Read through the description of each method below before deciding which is best for your seedlings.

Bottom Watering 

Bottom watering uses the principle of capillary action. In this process, moisture is drawn from a reservoir or an area of high water concentration to drier areas, rehydrating them without overly soaking the soil.

To bottom water your seedlings, place the tray or pot inside a slightly larger tray or a shallow bowl. Fill the larger bottom tray or bowl with water. Allow the seedling tray to sit in the liquid for an hour or two.

Check the soil moisture by placing your finger in the soil. If the soil feels dry, allow the tray to sit in the larger container for a little longer. As soon as the soil feels moist, remove the tray and return it to its usual position. Any remaining liquid can be used to water your houseplants.

Bottom watering takes longer than top watering. However, it provides a far more gentle way of watering your seedlings. Bottom watering also ensures that the soil takes on only as much moisture as it needs. This helps to prevent more severe issues such as rot from developing.

Top Watering

Top watering is the process of using a watering can or jug to pour liquid onto the soil from above.

Watering indoor plants and succulents is a lot different from watering plants growing outside. The growing medium used for indoor plants, particularly seedlings, is light and easily disturbed when watered. This can damage delicate seedlings or wash away freshly sown seeds.

7 Dont overwater seedlings
Be careful not to drown or disturb the seedlings. 

The following are some of the best how to water seedlings methods.


One of the easiest how to water seedlings options, misting your plants with a Plant Mister Spray Bottle ensures that your delicate seedlings remain hydrated with the danger of snapping the tender stems.

Misting only moistens the soil surface; it doesn’t sink into the soil. This means that you may need to mist the germinating seeds as often as once or even twice a day. As the seeds germinate and plants start to grow, they may need heavier watering.

Light Sprinkle

A watering can with a fine head, sometimes called a rose, provides a light sprinkle that gently moistens the soil around your growing plants. You can make your own sprinkler by using a pin or needle to puncture holes in the lid of a pop bottle. Fill the bottle with liquid and squeeze; a light spray should fall out, gently watering your plants.

How to Water Seedlings With a Watering Can

A Watering Can for Indoor House Plants can be used as your plants grow. These often have long, thin necks which emit a gentle stream of water. This helps to avoid accidental damage to your plants. Indoor watering cans also make watering hanging succulents and plants a lot easier.

How to Water Seedlings in the Garden

Some seeds are best started directly in their final growing position. Like those started undercover, these also require careful watering.

When they are young, water the plants every other day. Young plants growing outside may not require as frequent watering as those started in pots undercover.

A sprinkler may seem like an excellent way to keep your seedlings hydrated; after all, it does not emit as strong a flow of liquid as a hose, but it is not recommended. Instead, use a soaker hose or a watering can.

Soaker Hose

Similar to a regular garden hose, a soaker hose allows moisture to slowly leak out, gently hydrating your soil and plants.

Lay the soaker hose out along the soil of your garden or raised bed and turn on the tap.

The liquid released by the soaker hose soaks gently into the soil. If you have a large garden, a soaker hose is one of the most economical ways of watering.

Watering Can

A more labor-intensive how to water seedlings method, if you are using a watering can, make sure it has a long neck. This enables you to reach under the foliage and directly moisten the soil. A watering can with a small rose provides a light sprinkle that doesn’t damage young plants.

8 Watering can for seedlings

Use a watering can with a gentle spray.

Will Rain Keep My Seedlings Hydrated?

The main advantage of growing seeds in the garden is rainfall. As any gardener knows, plants always grow better after rain. However, growers in many conditions can’t rely solely on rainfall.

Unless your garden enjoys regular rainfall, watering plants is necessary. To reduce your usage, a rainfall harvest system enables you to store rainwater for use in your garden.

If you need help knowing how often to water your plants, a soil moisture sensor is an excellent investment.


Learning how to water seedlings is an important skill. Correctly watering from germination to transplanting ensures that your plants become strong and productive.

Here are some more how to water seedling tips.

Growing Medium

A good seed starter mix, such as Espoma Organic Seed Starter Potting Soil, retains water. Working vermiculite into the soil helps aerate the soil and aids in moisture retention.

Pre-moisten the Planting Medium

Moistening the growing medium before planting or sowing creates the ideal environment for germination. This helps to get your plants off to the best possible start.

Moistening the growing medium before planting is beneficial if you are starting small seeds that can easily be drowned or washed away. Sowing in an already moist growing medium means that you may only have to re-moisten the seeds again once they have germinated.

The easiest way to moisten your growing medium is to place it in a bowl and slowly add water. Mix the soil and liquid together, adding more liquid until the mixture is damp enough to hold itself together when squeezed into a ball. It shouldn’t be so wet that when you squeeze it, moisture drips out. If you overwater the growing medium, let it dry a little before sowing your seeds.


The size of the pot or tray affects how often you water seedlings. Smaller pots and trays hold less soil, meaning they dry out faster than larger containers.

Good Drainage

An important part of learning how to water seedlings is ensuring the soil doesn’t dry out. Ensuring that your plants don’t get too wet is just as essential. This can cause them to rot or become diseased.

Make sure that every tray and pot that you use has drainage holes in the bottom. This allows excess moisture to drain away. Don’t allow your pots to sit in standing water.


Mulch is just as effective on indoor plants and trays as it is outside in the garden. A light organic mulch such as straw, shredded leaves or grass clippings can be placed around growing seedlings. Wait until the seeds have germinated before mulching the soil.

9 Mulch around seedlings

Mulch helps the soil to retain moisture.

Cover the Trays

Many seed starter trays and propagators, such as the LeJoy Garden Propagator, come with a fitted plastic cover. This creates a humidity dome, trapping moisture close to your seeds. It also helps to maintain an even temperature around your growing plants.

You can make your own cover by placing pots and trays in a clear plastic bag.


One of the main benefits of starting your plants undercover, either in your home or a greenhouse, is that you can control the growing conditions.

The temperature has an effect on how much your seedlings need to drink. If your plants are too hot, they will take on more liquid to try and keep cool.

Aim to keep the temperature warm enough to encourage growth but not so hot that the plants are taking on moisture to stay cool.

Watch the Edges

The edges of pots and trays tend to dry out faster than the center. When you check the dryness of the soil, make sure that you check the edges as well as the center of the tray.

Time of Day

The morning is the best time to hydrate seeds and seedlings. This means that the plants have taken on enough moisture to survive the heat of the day. Watering in the morning, when the soil is cool, also means that less moisture is lost to evaporation.

Watering in the evening means your soil is wet at night and more likely to attract slugs and snails.

Rest the Water

Our final tip doesn’t help to reduce how often you water seedlings, but it can still help growing plants. The water supply in many areas is treated with chlorine. This can harm delicate plants. Allow tap water to sit overnight before using. This allows the chlorine to naturally filter away.

Allowing the tap water to stand also helps to warm it up to room temperature. Using cold liquid on your plants can send them into shock.

10 Let water stand before watering
Let the liquid stand before using it on your plants.  

Remember, not every plant has the same watering needs. Read the seed packet or ask at your garden store if you need clarification on how much watering your plants need.

If in doubt, it is far better to underwater than to overwater your plants. Overwatering can damage root systems and kill plants.

One of the most obvious signs of overwatering is the foliage turning pale green or yellow. This change in color happens when the soil is soaked and the plants struggle to take on enough oxygen.

Overwatering can lead to a number of serious issues developing. These include:

  • Root rot,
  • Drowning,
  • Mold,
  • Damping off.

Overwatered plants also attract undesirable insects or pests to the garden.

Can You Save Overwatered Plants?

It is possible to save overwatered plants if you act quickly. Signs of overwatering include:

  • Foliage fading to a pale green or yellow color,
  • Wilting,
  • Growth ceasing,
  • Mold in the pot,
  • A foul odor.

If you suspect your plant has been overwatered, cease watering until the soil has dried out. To work out when to water, stick your finger into the soil. It should feel dry. Another way to work out when and how to water seedlings or plants in pots is to pick up the pot. The more moisture in the soil, the heavier the pot. Only water when your pot feels light.

To save a severely overwatered plant, repot it into a new, clean pot. The new pot should have lots of drainage holes in the bottom. Loosen the soil around the edge of the pot and gently slide out the plant.

Carefully brush away any dirt that is on the root system. Cut away any slimy or brown roots. Retain only firm, pale roots. Discard the old soil and roots and sterilize your scissors.

Trim away dead or damaged leaves before repotting them in a new container filled with fresh soil. Water only when the soil shows signs of drying out.

11 Learn how to water seedlings

Learning how to water seedlings is a useful skill.

Learning how to water seedlings can be daunting. Following the tips in this guide should help you master this vital skill.

How to water seedlings 1 How to water seedlings 2