
I very nearly told him to water as needed but then another fella chimed in, “Yes, I need to know that too. I mean everything I read says to water as needed. But what does that mean?”
I realized that this was actually a valid question and a point of interest to many so I thought I ought to address that today.
One of the first things you have to understand about gardening is that we have to provide our plants with water. Because let’s be honest while there are some plants that will survive without adequate water but there are no plants that will thrive without adequate water. Surviving is not thriving (and flowering) so while this isn’t a sexy topic, it is an important one.

Most recommendations for watering your garden call for between one to one and a half inches of water every week. It is best to apply this in two applications of three quarters of an inch spaced several days apart rather than a single weekly application. It is bad gardening practice to water every day once plants are established. It is only during the establishment period that we water our garden plants daily, after that, a daily watering does more harm than good in that it trains our plants to put out only shallow roots when what they need is to develop a deep root structure. More watering may be needed when we start to stretch multiple 100 degree days together.

Most recommendations for watering your garden call for between one to one and a half inches of water every week. It is best to apply this in two applications of three quarters of an inch spaced several days apart rather than a single weekly application. It is bad gardening practice to water every day once plants are established. It is only during the establishment period that we water our garden plants daily, after that, a daily watering does more harm than good in that it trains our plants to put out only shallow roots when what they need is to develop a deep root structure. More watering may be needed when we start to stretch multiple 100 degree days together.

When the rain gauge shows that we received just 1 inch of rain, what that really means is that we got 27,154 gallons of water per acre of ground! Just for the record, this water weighed in at 113 tons or 226,192 pounds. Just one inch of rain really puts down some water! That is one reason I highly recommend employing some kind of rainwater collection system – but that is a topic for another article.
So, one inch of water is actually quite a bit, that’s why, unless you are container gardening, I recommend using a sprinkler. The question is, how long do I let the sprinkler run? The answer is I do not know! But while I cannot tell you how long to run your sprinkler, I can tell you how to figure it out.

For those of you lucky enough to have a drip irrigation system here is how you can calibrate it:
- Put your length of hose into a 5-gallon pail.
- Measure the amount of time it takes to fill up the pail.
- Decide how many gallons you need for each plant.
- Now you know how many gallons your garden requires – and how long it takes to put 5 gallons onto it.
- Divide the number of gallons by 5 and you’re in business.
- Note: Drip irrigation takes a LOT longer than you might think to fully water a garden.

This is actually a fascinating process and luckily for gardeners, water is the universal solvent. This means that more things will dissolve in water (eventually) than any other liquid including acids. Soak something in water long enough and it will dissolve, nothing resists the slow and steady weathering action of water. Not only that but water tends to stick together in drops rather than spread out evenly in a thin film. This stickiness is called its capillary action. When we combine the stickiness of water with its ability to dissolve minerals and fertilizer salts, this means that plants can suck food up into their leaves. As one molecule rises up the plant, shrub, or tree, it literally drags other molecules behind it. You can see this work in your own kitchen. If you put an edge of paper towel into a bowl of water, the water will “climb” the paper towel. This is capillary action at its best and it is why watering the bottom of houseplants is often recommended. The water will eventually climb up the soil into the top of the pot and evenly water the plant. By the way, the world’s record for rain belongs to Mt. Waialeale, in Hawaii, where the average rainfall is 450 inches per year, the single year record is 642 inches during one twelve-month period.
Let’s Understand Water a Bit Better
H2O is the familiar chemical representation of water and we all know that this means water is composed of one atom of oxygen bound to two atoms of hydrogen. Water pours or comes out of hoses or goes up a plant because of the arrangement of these molecules. You see, the hydrogen atoms are on one side of the molecule (they’re negatively charged) and the oxygen is on the other (it is positively charged) and so each molecule of water acts like a mini-magnet. All these mini-magnets stick together to form a water drop.
Did you know that a drop of water is shaped like a teardrop because gravity sucks it downwards? Without gravity, a drop of water would be round like a ball. Just check out a video of astronauts on the space shuttle playing with liquid and you will see that the water is not tear drop shape but forms a wiggly-giggly circle in the vacuum of space.

1. Get to know your soil. Dig into your garden and find out whether you have clay or sandy soil. It makes a big difference in your drainage. Keep in mind that clay-laden soil presents special watering challenges. Clay has an electrical charge that draws water, pulling it away from plant roots. In dense clay, little room exists for passages that permit the exchange of essential gases with the air above ground. Clay also drains slowly. Water flows more easily through sandy soil. But if it's too sandy, water may leach out too quickly and take dissolved nutrients with it. Both clay and sandy soils can be turned into a preferred loam by mixing in organic material, such as compost. You can check how fast your soil absorbs water using any type of cylinder, such as a coffee can with the top and bottom removed. Push one end into the soil a few inches. Fill the can with water and let it drain completely. Fill it again, and then see how long it takes for the water level to drop 1 in. If it takes more than four hours, you've probably got a drainage problem that could harm plant roots. Amending the garden soil with plenty of good quality, organic, microbe rich compost or even switching to raised beds may be the solution if that site is your only option for a garden. A friend of mine in southwest Florida had the opposite problem. His garden soil was dredge spoil, which is essentially sand. Water drained faster than you could say ‘alligator’. It took the addition of several 50-lb. bags of compost to the little garden strip to slow it down. Compost is garden magic in a bag! It improves clay soil as well as sandy soil and even if your soil has perfect drainage adding compost will only improve the plants that grow there.
2. Keep water percolating in the zone. The root network is the critical area of watering. And the depth varies among plants. In general, we're talking about the first 6 in. to 8 in. of soil. Keeping that section moist should prevent plants from being parched by thirst or stressed from binge drinking. With a good garden soil, you should be able to squeeze a little dirt into a clump that will break up easily if you gently bounce it in your palm.
3. Water before you mulch. Mulch helps conserve water in your soil by shielding the ground from the sun’s hot rays that can quickly burn off moisture. But it's a good idea to soak the soil before you lay on that first layer of mulch. Just as the mulch hinders evaporation, it also slows penetration of moisture to the roots. It's more efficient to get the water down first, then mulch. It also may initially save your plants from waiting for water to percolate through the mulch when they are accustomed to getting it right away. The mulch, of course, also will suppress those thirsty weeds trying to elbow their way to the fountain. So I always recommend you water first then apply your mulch and then water the mulch in.
4. Read the leaves. Don't let leaves fool you. If they're drooping in the hot, midday sun, you need not necessarily be alarmed. The plants may just be protecting themselves by exposing less surface to the sun and conserving their water, this is normal in many plants. They often do this when they are unable to pump water up the stem quickly enough to offset the loss through the leaves. If the same plants are drooping in the morning or at night, then you can rev up the water wagon. But don't cause a flood. Saturated soil drives out the air that plant roots need, and plants will drown. And there's no reason to water the leaves. That can encourage a variety of fungi that develop in moist conditions, causing mildew and blight.
5. Get a bigger bang per bucket. Consider the life cycle of the plants in your garden when you water. For example, recent transplants need frequent, light watering to accommodate their shallow, young roots and ease the shock of being pulled from their six-packs. Steady watering also is critical at the time of flowering and fruit formation. For some crops, like tomatoes, yields may improve but some flavor may be lost with too much or too little watering as fruit ripens. But, with carrots and cabbages, for example, watering should be reduced as the crop reaches maturity to keep the vegetables from splitting. Once plants are established, more harm than good is done by giving them a daily sprinkling. If only the soil surface gets wet, roots will look up, not down, for their drinks. Deep, less frequent watering works better.
6. Grow thirsty plants together. If you have the space in your garden, you can save yourself some trouble by grouping plants according to their water needs. For example, you wouldn't want to plant your herbs next to your lettuce, even though they often wind up together in the salad bowl. Generally, herbs thrive in drier areas, while lettuces like it lush. If the lettuce gets the water it needs, the herbs are likely to be lush, too, but tasteless. If you water to suit the herbs, chances are the lettuce will turn out bitter. By grouping the plants according to their watering needs, you won't waste water where it isn't needed.
7. Choose your time wisely. Early morning, late afternoon, and evening are usually best for watering because the cooler temperatures mean less water will evaporate. Limiting your watering to these times is a particularly good idea if you use overhead sprinklers. It’s also safer not to water at night, as the leaves will remain wet, which may encourage disease. In arid places, however, some people decide to risk night watering to give the water longer to soak into the soil and cut evaporation from the sun. Know your area, know your garden, and make the best watering choice for you.
8. Know when to say when. According to a common rule of a green thumb, a garden needs about 1 in. of water per week. Divining how much the garden is actually getting can be a little tricky. You can estimate by using a rain gauge to track precipitation. The gauge should be near the garden but where water splashing off pavement or overhangs won't affect the reading.

This is very true. Wilting plants and dry soil are a sure sign of water stress. However, don't just look at the wilting leaves. If the soil is moist, the wilting may be due to other problems such as disease or over watering. Some plants, such as eggplant, will naturally wilt during hot periods but recover when the temperatures cool. They may not need watering. If the plants aren't indicating it's time to water, the soil will. You can also stick your finger in the soil. If you dig down 3 to 4 inches into the soil and it's still dry, it's time to water.
Happy Gardening!!