OK, so let’s discuss how we achieve the “right” amount of water for our seedlings. You’ve probably heard that too much water isn’t good and too little isn’t good, either. So, let’s navigate the ambiguity!
First, let’s point out the painfully obvious stuff. Soil that looks or feels wet is wet. Soil that looks or feels dry is dry. This is your primary indicator as to whether the soil needs more water or not, there’s not a deeper mystery to it!
When you spray water onto soil, what happens is that water will wick throughout the soil. If you only provide a light surface watering, once that wicking occurs, you’ll be left with a fairly light moisture level throughout the soil.
Surface moisture is great for the initial germination. But, once those plants germinate, we need water throughout the soil. The seedling will put down a tap root, seeking more water. Our goal is to help it find it, immediately!
We’re aiming for complete saturation, but not oversaturation. We like to call it “moist, but not wet.” It can take a surprising amount of water to get there. For example, with a 1020 seeding tray, we’re often laying in 2-3 cups of water in our initial watering! (Thus, the pressure sprayer discussed yesterday!)
Once you get to good saturation, take it easy. Watering maintenance only needs to happen once the soil looks dry, not continually. We do sometimes give our seedlings a really light mist every day or two, but it’s just enough to wet the leaves and maintain humidity.
When using trays, it’s common to see some areas go dry and others stay wet. It’s perfectly OK, if not even beneficial, to only water the dry areas. Ideally, you want to achieve a fairly even balance of moisture across the soil.
Lastly, if you get green stuff, that’s algae or moss. It’s a sign that your humidity is too high, often caused by too much water. Back it off, let things dry up a bit and use that to help achieve a better balance.
This stuff will become second nature after awhile. You’ll start to “feel” the optimal amounts of water, allowing you hit the mark every time!
