Watering 101

standing water in a bed

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.

Soil lies.

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.

dry dirt under water

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.

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13 Comments

  1. Boy are you right about this. It seems like every summer I have to re-learn it, too, why is that? Last night, before turning on the water in the berry patch, I dug down to find what I thought was a gopher tunnel. No tunnel, but I realized how moist the soil was, and that my plants most likely needed NO water, despite 109 degree temps that day. Glad I caught it before I flooded the poor berries and wasted valuable water. You really do have to dig in and check.

  2. Have you ever tried, with any success, one of the moisture and pH probes that are sold at Lowe’s and HD for about $10.00?

  3. Yep. Great advice to remember.
    @Max: The more you pay for a moisture meter, the better it works. The technology to make accurate meters exists and is used on large farms. The toy versions you can get at HD or wherever aren’t very accurate and aren’t very durable.

    • Funny you should ask — I’ve got a pair of clay pots sitting here waiting to be glued up into a DIY olla. Will report back later!

  4. When this dry-soil-looking-wet has happened to me its been because I let the soil dry out too much. Might be hard to keep your soil moist enough in SoCal.

    I also wonder if lack of absorption is related to lack of microorganisms and general poor soil health/balance – not necessarily lack of nutrients. Any thoughts?

    • Definitely. This bed had only held a few things on a drip line, so it was quite dry in most places. I thought it would make a good example of the principle, though. In general, healthier soil is going to absorb, hold and drain water better than other soils. Of course, it’s hard to have healthy soil if you over- or under-water! It’s all connected…

  5. Pingback: The Friday Five: My Picks of the Week (July 1st – July 5th, 2013) | Jeff Parker Cooks

  6. One of the things I have tried that works, especially for a new bed, is to poke the soil multiple times with a bamboo stick as far as you can, then water. After watering take a small hand rake and scratch the surface to “reseal’ the holes to keep the water from evaporating. Now you can plant and mulch. I read this method in ‘dry farming.’

  7. That soil looks like a or of bagged soil that has peat or peat mos in it. Not only terrible for global warming, and destroying the peat bogs, but also it repels water once dry and so is notorious for being hard to water, as you found,

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