One thing that can be a little tricky to figure out is how much water to offer your seedlings. It’s very likely you might be underwatering your seedlings, so we’re going to talk about our general thoughts and practices.
It’s quite common for many gardeners to give a light, surface watering of the soil. What happens in this case is the soil will wick the moisture below and the overall moisture content of the soil will be relatively dry. Remember, our seeds are going to throw down a tap root and try to get moisture at the bottom of the soil. We need sufficient water throughout the soil to satisfy the plant! Sufficient watering promotes good, deep rooting habits from our plants.
Our watering sessions are often as much as 2 to 4 cups of water per tray. This might seem like a lot, especially for seedlings, but it gets widely wicked and distributed into the soil. We’re generally aiming for moist, which is somewhere between dry and soaking wet. This is one reason we like our pressure sprayer so much, it easily allows us to get to this moisture level throughout the soil.
You may find that when you’re properly watering your seedlings that your soil will have a tendency to produce mosses or algae on the surface. If you’re using humidity domes like we recommend, this is what those little vents are for. This doesn’t indicate you have too much water, but rather high relative humidity! Simply open up those vents on your domes and you’ll find the “extra greenery” will largely be kept at bay. If your domes don’t have vents, be sure to pull off the dome at least a couple times a day to reduce relative humidity.
It’s time to water your seedlings once the surface of the soil starts to look dry. If the surface is dry, likely so is the rest of the soil. It’s generally better to perform less frequent, thorough watering than it is to perform more frequent watering with less water. If only some of your soil looks dried up, it’s perfectly acceptable to only water portions of your soil.
If you inadvertently get a little too much water in your soil, just leave your humidity domes off your plants for a day or two. That moisture will evaporate right up and your plants will be fine!
