I've been dabbling around with my little mountain-side garden for, oh … five or six years now, and I've learned a few things along the way. It seems like I've learned more about what doesn't work than what does, but that's probably because failure is more evident than success. Unless it's spectacular success. Average success tends to go unnoticed.
One of the first lines of wisdom I gathered was about watering. This wisdom breaks down into three categories: what kind of water, how much water, and when to water.
What Kind of Water
I learned early in that rainwater is magical stuff. I can water and water with the hose and our well water and get only a marginal response from our plant life. But one decent rain and everything greens up and bursts into bloom. What gives with that? We don't even have all that chlorine, fluoride, and who knows what else in our water. There is no mineral taste to it. It's great water!
But our well water is on the hard side. Our fixtures calcium up after a short while and things like shower heads and sink aerators have to be soaked in vinegar regularly to keep them flowing. Can that calcium be affecting the plants? Maybe temporarily messing with the pH of the soil? I don't have a definitive answer to that yet, but it is my working theory.
Harvesting and storing rain water is a good answer, as long as you don't store it too long. Even Unicorn Drool – I mean rain water – will go septic if stored too long. Building a solar still using a sheet of clear plastic is pretty straight forward, uses no fuel or electricity and works mostly unattended while turning out some distilled water for use on plants. You do have to rinse out the evaporator trays every morning, so it takes water to continue making water, but its one way to remove the calcium.
How Much Water
Early on, I figured, “If some water is good, more is better” and I tended to water every day. This is bad. Okay: it's good for seedlings. Seedlings need a SMALL amount of water regularly so their teeny little roots don't dry out and cause the baby plant to wither and die. But even here, too much water at once causes the seedlings to flop over in the mud and rot.
Once the plant is better established, daily watering causes the plant to become lazy. Its root system will grow only to where it finds enough water to survive. By watering it daily, the roots will be under-developed. If you then miss a day or two, the plant suffers. By watering once or twice a week, the roots will reach farther out and down and will be better able to support the plant.
Most plants seem to do well with 1 inch of water (per square inch) per week. This is actually more water than I would have thought, and when I'm watering with a wand, I have to force myself to stay on each raised bed long enough to give it a thorough soaking.
In a 4 x 4 foot raised bed we're talking 2,304 square inches of surface. One inch of water on each is 2,304 cubic inches of water. There are 231 cubic inches in a US Gallon. 2,304 divided by 231 is 10 gallons of water per 4 x 4 box per week. If it takes 3 minutes to fill a 5 gallon bucket with my watering wand, then I have to stay at each box for a full 6 minutes to do the job once a week.
But I find it works better to split it in half and do the job twice a week: the plants suffer less that way. And, of course, if you get rain, you can deduct that from your weekly watering quota.
When to Water
The short answer is “early”.
Just as bright sunshine will cause you to sunburn faster if you come out of the pool and stay wet (without sunscreen) your plants can sunburn if left to stand in the summer sun while wet. Water before the sunshine gets strong.
You also don't want to leave wet leaves standing overnight. Watering in the evening can encourage fungus and blight in the leaves because they stay wet too long.
This, of course assumes you are using a standard watering system: sprayer, wand or sprinkler. If you're using a soaker hose, then this point is moot because the water stays at ground level or below. Turn it on when it's convenient.
Watering once or even twice a week can seem like not enough if you have soil with a low water retention factor. Our red clay has properties similar to concrete when it's dry, but when water comes along the crystalline structure of red clay allows water to flow through it surprisingly quickly. This is great when you desire to install a septic system, not so great when trying to keep your plants hydrated. Increase water retention by adding coarse ground vermiculite or organic matter such as compost or peat. Or both. Garden soil made of equal parts composted cow manure, peat, and vermiculite is great stuff.
You can also help keep the sunshine from sucking surface moisture out by using mulch: wood chips, straw, or grass clippings (added in thin layers so they dry out or they'll mold). If you use straw, watch out for slugs.
If you use a sprinkler system, set a rain gauge inside its pattern so you can gauge how much water has been delivered.
You can make a great liquid fertilizer too. Put a couple big handfuls of comfrey leaves or grass clippings in a 5 gallon bucket. Weight them down (a disk cut from hardware cloth and a few rocks does well) and cover with a couple gallons of water. Put a lid on and let it steep for a couple of weeks, then filter out the goop and store the “tea” in a sealed container. It smells awful, but a few tablespoons of this in your watering can (with water) is like Red Bull to your plants. Do this just as your veggies or berries are setting fruit and you'll get bigger, better produce.
Some things: tomatoes and watermelons, for example, need a lot more water when they are producing fruits than other plants. Others, such as radishes, prefer less. Grouping plants with similar water needs together in your garden helps to remember their needs and reduces over-watering things that don't need so much.
That's what I can think of. What watering wisdom do you have to share? Feel free to chime in via a comment.
Photo by Fotolia/naypong