The pots are filled and the seeds are lightly buried and gently packed in the perfect growing medium.

Now comes the stressful part: am I giving my young plants too much water or too little? How do I know the perfect amount of moisture to achieve growing success?

If you ask these questions, you are not alone. I spent many years watching my seedlings start beautifully before suddenly wilting to death or succumbing to mould and rot until I learned how to give the plants just the right amount of water.

Most newly planted seeds and young seedlings need watering about every second day. Of course, there are a lot of factors that affect how often you need to water including temperature, pot size, or growing medium.

Every growing season is different, and whether you start your seeds indoors or plant them directly in the garden, let’s learn how to tell exactly when a seed and seedling needs water, plus tips for successfully watering seedlings.

Factors That Determine How Often You Need to Water Your Seedlings

Seeds and seedlings will generally need water every 1 to 2 days if they are grown indoors or in the garden. Seeds and young plants grow best with a consistent and even supply of moisture where the soil is neither soggy nor dry.

Of course, “how often” is determined by several factors including temperature, soil type, tray size, and heat from grow lights or heat mat, so in a hot dry year you may need to water every day or even twice a day. Make sure to check the soil every day in case watering is required.

Water your seeds and seedlings when:

The Top 1 cm (1/2 inch) Of Soil Is Dry. Since most seeds are shallowly sown and seedlings have short roots, they will grow best when the soil around them is moist so water when the top layer of the soil is dry (actually, you want to water them before this layer completely dries out so the plants always have access to moisture). You can often see when the soil has dried when it becomes a lighter colour. Otherwise, try the finger test: stick the first digit of your finger into the soil: if it is dry it is time to water; if the soil is still damp it can probably wait until tomorrow.
Trays Feel Lighter: Every day or so, lift your pots and trays to see how heavy they are. If they feel light, they are dry and need water. If they are heavy, they probably still have enough and can wait another day. This is the easiest way to tell if indoor plants need water and with a little trial and error, you will quickly learn the ideal weight for your plants.
Look At The Plants: Young seedlings are very susceptible to water variations and will quickly droop if they don’t have enough water. Drying plants won’t look as plump and will start to droop and wither. If you notice this, water immediately!

You have a lot more leniency with watering seeds and seedlings in the garden as opposed to those grown indoors and in pots.

The soil in pots will dry out a lot faster than garden soil, and the moisture is limited whereas outdoor plants have the benefits of water deep in the soil and early morning dew.

As seedlings get older, their water requirements become less exacting. After a week or so after germination, you can probably cut your watering down to every second day. As they get even older, they benefit from a less frequent and deeper watering once or twice a week.

What Happens if You Overwater Your Seeds?

How Often To Water Seedlings – Good Watering Practices For Seeds And Young Plants 1 — @oncebutaseed

The obvious problem with underwatering seedlings is that they will dry out. In extreme cases, they will wilt and die.

Mature plants can rebound after drying out and withering slightly but young plants are often too delicate and are not resilient enough to sustain themselves without water even for a short period.

Another problem with letting seedlings dry occurs if your growing medium has peat moss. Dry peat moss becomes almost impervious to water and will shed any water you pour on.

What To Do If Plants Are Dry

If plants have dried out, get water on them as soon as possible and hopefully you caught them in time. If the growing medium containing peat moss is overly dry, soak it in a tray (see Bottom Watering below) until it has become sufficiently rehydrated.

What Happens When Seeds And Seedlings Are Overwatered?

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You might think that wilting seedlings is the worse problem you can face so you add lots of water, but this is not often the best solution. In most instances, it is better to underwater than overwater. Overwatering seeds and seedlings can lead to issues such as:

Root Rot: As soil becomes saturated, the tender roots of the plants can rot.
Drowning: Since plants breathe, they can also drown. Lots of water fills air pockets in the soil and the plants drown from lack of oxygen.
Mold: Many different kinds of mold flourish in damp environments
Damping Off: This is a fungus that kills young plants in wet environments.
Insects: Most undesirable insects (what we would normally call “pests”) also thrive in damp.

How To Help Overwatered Seedlings

For seedlings in trays, move your plants into a sunny, dry, and airy place to facilitate drying.

If you are growing in the garden, don’t water your garden until it has sufficiently dried out (and hope it doesn’t rain).

The Proper Way to Water Your Seeds And Seedlings

Sometimes, we will have the greatest success with a plant if we start it in a container. Many vegetables, such as tomatoes, cucumbers, and peppers are excellent for transplanting and lots of flowers benefit from starting early indoors as well.

There are 2 ways to water seedlings: bottom watering, and top watering.

Bottom Watering

Bottom watering uses the principle of capillary action, where water is drawn from areas of high water concentration to areas that are dry (or have a lower concentration of water).

Place your tray or pot inside another tray or shallow bowl. Fill the bottom tray with water and let your seedlings sit in it for an hour or two.

After this time, check the soil moisture. If it is still dry let it sit longer. Once the soil is moist enough, dump out any remaining water.

Bottom watering is by far the most gentle way you can water your seedlings and has the advantage the soil takes on the right amount of moisture that it needs.

Top Watering

How Often To Water Seedlings – Good Watering Practices For Seeds And Young Plants 3 — @gardena.southafrica

Top watering plants means pouring the water onto the soil from above.

Watering indoor plants is a whole different ball game than watering the garden. In particular, the growing medium of indoor plants is light and will be easily disturbed by watering which will wash seeds away or break the stems of seedlings.

Here are the best ways to top water potted seedlings:

Mist

Many indoor seeds and seedlings will do well with a light mist from a spray bottle. This might have to be done every day (or even twice each day) since it only waters the surface and does not sink into the soil.

Once the seeds have germinated and started leafing out, they may require heavier watering.

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Light Sprinkle

If you want a heavier watering than a spray bottle, use a watering can with a very fine head (or rose). You can also make one yourself by punching a few small holes in the lid of a pop bottle.

Water Gently With A Watering Can

No matter how you water, always water gently! If you are using a watering can, make sure it has a small rose or thin neck to avoid damaging the plants.

Look for a small indoor watering can as opposed to the large, plastic bulky ones intended for outdoor use.

Secrets To Watering Your Seedlings The Right Way

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Here are some tips that will really improve how you water your seedlings.

Moisten Growing Medium Before Planting: Start with a properly moistened growing medium, by moistening it before planting or soaking the tray in water. This creates an ideal moist environment that gets your plants off to a good start. This is especially important with small seeds so you can water them lightly to maintain good moisture.
To moisten the soil first, put your growing medium in a bowl. Slowly add water and mix it in until the desired wetness. The soil should be damp and hold itself together when squeezed into a ball, but not so wet that you can squeeze water out. Then, fill your pots with moistened soil.
Soak the tray in water by the bottom watering method discussed above.
Mulch: Just like in the garden, you can mulch your indoor pots and in trays with an organic mulch. A light layer of straw, grass clippings, and shredded leaves can be put around seedlings. Keep the mulch chopped fine so it is easier to place around the plants.
Control The temperature: One advantage of growing indoors is that you have (almost) complete control over the growing conditions. Temperature is an important factor in water absorption, so try and keep the temperature just right for the plants you are growing, but low enough that the water won’t evaporate too quickly.
Use The Right Growing Medium: A good seed starting mix will retain water. You can purchase seeding mixes or mix your own. Vermiculite is an important component of a good growing medium for aeration and water retention. Peat moss is also very commonly used in most commercial growing mediums, but leaf mold is a much more environmentally sound option.
What’s Your Size?: Smaller tray needs more regular watering because there is less soil to hold moisture so they dry out faster. Know your pot size and adjust watering accordingly.
Cover Trays: Many pre-purchased trays come with a clear plastic cover that traps moisture. Sometimes call a humidity dome, you can easily build your own with clear plastic stretched over the tray or from an empty milk jug with the bottom cut off. Remember that these also trap heat which can dry them out faster.
Ensure Good Drainage: While you don’t want your plants to dry out, you don’t want them to get too much water either or they can rot and become diseased. Make sure that all your pots and trays will allow excess water to drain out, and don’t leave them sitting in a tray with standing water.
Keep A Watch On The Edges: Large trays will dry out faster on the edges than in the middle. Make sure you check the moisture all over the tray and not just in the middle to get an accurate moisture reading.
Rest The Water: This doesn’t help reduce the frequency of watering, but it is a good idea before watering your plants, especially if you are on a treated municipal water supply. Most water in towns and cities is treated with chlorine which is not good for your plants. Let the water sit overnight before using watering your plants to allow it to naturally filter out the chlorine.
Water In The Morning: The best time of day to water your seeds and seedling is in the morning. Watering in the morning means the young plants will have sufficient water to survive the heat of the day. In the morning, the soil is cooler so less water is lost to evaporation, and it keeps your soil from being overly wet during the night which attracts slugs, snails, and other undesirables.

Can I Water During A Drought?

There is nothing worse than watching your plants die during a hot dry spell, especially when there is a ban on water use.

Whether or not you can water your precious plants during a drought depends on your municipality. Always check with your local government on what restrictions are in your area. No matter how much you want to, never water if such action is prohibited.

If some watering is permitted, indoor and potted plants will often require less water than a garden because you only have to water the soil on the pots and not unproductive soil.

You can also control the environment of indoor plants to conserve moisture by adjusting the ambient temperature or moving them to a different location where they won’t dry out so fast.

How To Water Seedlings In The Garden

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If you are like me, you prefer starting your seeds directly in the garden. It is delightful watching them spring forth and turn into a delicious jungle of greenery.

When your seedlings are young, they will do best with regular watering every second day or so.

As the soil dries out and we reach for our sprinklers, remember this isn’t the best way to water a garden.

A sprinkler is actually the least desirable to water the garden because a lot of the water is lost to the atmosphere or ends on the foliage where it evaporates or burns the leaves.

Here are some good ways to water seeds and young plants in the garden:

Soaker hose

A soaker hose looks like a regular garden hose but it is permeated to allow water to slowly leak out.

Lay it out along soil near the stems of your plants and all the water goes directly to the roots. They are also very economical for large gardens.

Watering Can

While this is more labour intensive, you can get a can with a long neck that allows you to reach under the foliage and put the water directly into the soil.

Make sure the watering can has a small head (rose) that will provide a light sprinkle so as not to damage or deluge the young plants.

Light Spray

How Often To Water Seedlings – Good Watering Practices For Seeds And Young Plants 7 — @moestuin_avontuinier

A simple garden nozzle is certainly the cheapest and simplest way to water but this isn’t the best way to water for reasons similar to a sprinkler.

If you use a nozzle, make sure to water with a light spray or fine mist otherwise an intense blast can crush tender seedlings or disturb ungerminated seeds.

Isn’t Rain Enough?

The best advantage of growing seeds in the garden is you can take advantage of all rain. However, rain isn’t always enough.

For many years we do not have to water our garden, but there are several seasons that are far too dry for the plants to grow. Is rain enough?

There is no answer for this as it depends on where you live, your climate, rainfall, drought conditions, and so much more.

Conclusion

Watering your plants can sometimes be a scary moment. Did I overwater them? Maybe I didn’t give them enough?

Or the ultimate when you remember on your drive to work in the morning that you forgot about them completely. Hopefully, this guide has given you some ideas on how to give your seedlings just the right amount of water.

Written By

Amber Noyes

Amber Noyes was born and raised in a suburban California town, San Mateo. She holds a master’s degree in horticulture from the University of California as well as a BS in Biology from the University of San Francisco. With experience working on an organic farm, water conservation research, farmers’ markets, and plant nursery, she understands what makes plants thrive and how we can better understand the connection between microclimate and plant health. When she’s not on the land, Amber loves informing people of new ideas/things related to gardening, especially organic gardening, houseplants, and growing plants in a small space.