This is watering 101. Those of you who have been gardening for a while have probably learned this the hard way. Those of you just starting out may find it helpful.
It looks wet, but it’s bone dry a fraction of an inch beneath. Or it looks dry on the surface, but it’s actually quite wet below. Or it’s wet, but only for one inch down.
The only way to find out if you’ve watered your garden enough is to stick your hand into the soil and make sure. You can’t garden without getting your hands dirty.
This is one reason why one of the most common questions, “How much do I water?” is one of the hardest to answer. The answer will vary, depending on your soil, the weather, the method you use to water, how often you water, and what you’re growing. In the end, you just have to use your hands and your common sense to figure it out. There is no formula.
In the picture above, you see the surface of the soil in one of our raised beds. This is imported soil, the kind that comes in bags. It doesn’t hold water in pools like clay soil does, it doesn’t sink in fast as it would in sandy soil. It’s actually pretty tricky to water because it seems like it should sop up water well, but I think all the organic matter in it actually slows absorption.
At any rate, I’d been watering this bed for some time with a sprinkler hose, waving it back and forth until I got bored. The water sunk in at first, then started to pool on the surface, and the pool lasted for a long time. At this point, a beginner might think she’d watered enough, but I’ve been fooled often enough before.
I reached down into the bed and scraped at the soil. A fraction of an inch beneath the wettest area, the soil was still perfectly dry. That’s what I tried to capture in the picture below–see all that dry soil? It was just beneath the surface of the puddle. I wasn’t done watering.
In general, you need to be sure that the soil in the bed is evenly moist. Not soggy and soppy, not dry, but pleasantly moist and springy. Over-watering can be problem as much as under-watering. If you know your soil tends to hold water, it may pay to dig before you even start watering. You may find you don’t need to water at all.
In a regularly watered bed, the deeper you dig, the more retained moisture you are likely to find, but the first few inches dry out fast. Older, deeper rooted plants don’t mind this so much if the top dries out, because they can reach deep for water, but if you’re dealing with young or shallowly rooted plants, you have to be very careful with the first five inches or so. Don’t trust your eyes. Trust your hands.