How Often Should You Water Seedlings? Here's the Best Method

Know the signs when your seedlings need more water

Whether starting vegetable seedlings indoors or outdoors, keeping them properly watered is key for strong, vigorous plants.

Seedlings need to be watered once a day, but that rule isn’t written in stone. Depending on the growing conditions, some seedlings need a light spritz twice a day while others are fine being watered every other day.

Overwatering, however, is just as detrimental to seedling health as lack of water. Understanding the signs when seedlings need water is more important than sticking to the once-a-day frequency rule.

Here’s what you should know about watering seedlings.

How Often to Water Seedlings

• Seedlings need to be watered at least once a day to keep the soil evenly moist, but not soggy.

• More frequent watering is required if the soil dries out faster because of strong light exposure or warm temperatures.

• Watering frequency will also have to be increased as the seedlings grow.

How Often to Water During Germination

Seeds need the right amount of water to germinate successfully. Commercial potting or seed-starting mix is often pre-dampened, but if it looks or feels a bit dry, spray it with water before planting the seeds.

If it is dry to the point where it does not cling together if you gather some in your hand, add water to a solid bottom tray and allow the seedling tray with soil to soak up the moisture for an hour, then pour off the excess water.

Once the germination process has started, insufficient moisture brings the germination process to an irreversible halt so make sure to always keep the soil evenly moist. 

How Often to Water Seedlings

Water whenever the surface of the growing medium looks or feels dry. That can mean daily watering, more than once a day, or every other day.

More frequent watering is usually also necessary if you are using a heating mat to speed up germination, which is a common practice for tomatoes and other seeds that need warm temperatures to germinate.

Placing the seed trays under grow lights, which is recommended for seeds that need light to germinate, also dries out the growing medium faster.

How to Check Soil Moisture

Check the moisture at least once a day. The indicator is the moisture level at the surface because seedlings don’t yet have the same deep roots as established plants that let them draw moisture from deeper soil levels.

A dry soil surface tends to look crusty and light in color whereas a moist surface is dark. Touch the soil surface with the tip of your index finger. If it feels dry, it is time to water.

The Right Way to Water Seedlings

Overly wet soil is one of the causes of damping-off disease, a fungal disease that can quickly kill seedlings. Watering seedlings from the bottom helps prevent the fungus. Always make sure to use well-draining potting mix or soilless potting mix.

1. Place the containers or pots on a solid tray and add ¼ to ½ inch of water to the bottom tray for 10 to 30 minutes.

2. Use your finger to touch the top of the soil to ensure the moisture has reached the top of the growing medium, then remove the tray with water.

3. Depending on how much or how little water has been absorbed, increase or decrease the amount of water in the next watering.

In addition to moderating the amount of water the seedlings get, bottom-watering instead of directly watering also avoids damaging the delicate and tender seedlings. It does not take more than a light mist from a spray bottle to knock over a tiny seedling.

5 Tips for Growing and Watering Seedlings

1. Check the soil moisture at least daily or twice a day. Always check the soil moisture before you water and don't water unless the surface of the soil feels dry.

2. Never let the soil dry out completely. Water regularly but moderately to keep the soil evenly moist.

3. The bigger the seedlings get, the more water they need. Adjust the watering frequency and amount accordingly.

4. Water seedlings from the bottom. This avoids knocking over the delicate stems of young seedlings.

5. Water freshly transplanted seedlings immediately. When they're outside or in their larger pot, give them deeper water than when they were in the seed starting cell.

Frequently Asked Questions

How often should I water my seedlings?

Seedlings should be watered between twice a day to every two days depending on how fast the soil dries out and how much water the seedlings absorb. There is no hard-and-fast rule about watering frequency; instead, learn how to check when seedlings need watering.

Can I use a spray bottle to water seedlings?

Watering seedlings with a spray bottle is generally not recommended, with one exception. Seeds that are placed on the soil surface because they need light to germinate dry out more rapidly than seeds buried in the soil. Gently misting those surface-sown seeds with a spray bottle a couple of times a day until they germinate ensures they stay moist. Once they start to germinate, start bottom-watering them as any other seedlings.

Should I water seedlings from the top or bottom?

Watering seedlings from the bottom instead of from the top is the better method because the tender seedlings aren’t at risk of getting damaged from a heavy water flow and there is less chance of overwatering them. Just remember to empty the bottom tray or take it away after 30 minutes at the most.

Read the original article on The Spruce.