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Watering the Garden

Plants rely on water as an essential element for successful growth.  Here are some watering tips:

The best time to water is in the early morning. Watering during the middle of the day can result in wasted water due to evaporation from wind and/or heat.  Avoid watering in the evening and letting the plants remain damp all night.  This can promote fungal diseases and disease organisms.  Watering all night may be the best time as it washes bacteria and fungus spores off the plant before they can do any damage.

Watering less frequently and deep is a very effective use of water.  Shallow watering encourages shallow root systems.  This will make the plants more drought sensitive by causing the roots to stay near the soil surface where it dries out quickly.  Even if the garden is watered daily, if it is done too lightly it may not be enough.  The top five to eight inches will stay moist while the deeper soil is dry.  There may be no sign of moisture stress; no wilting, but plants will be stunted from lack of root development.  Root crops like carrots and beets will be poorly developed or woody.  However, light frequent irrigations are needed for seedlings or for growing plants with higher moisture needs like radishes, Chinese cabbage, and celery.

The use of a timer eliminates the need to remember to shut sprinklers off.  An inexpensive timer can be hooked to your hose, and it will shut off your hose after the amount of time that you decide; one that I recommend is by Melnor and is called a Daily Water Timer.

Soil quality effects watering effectiveness.  Deep loose soil holds moisture but allows it to drain and not pool.  Higher clay content also holds more moisture but with too much clay in the soil, it will drain poorly and will be slow to dry out.    Sandy soil has little water retention capability so needs more irrigation and is more vulnerable to drought.

More organic matter content translates into more water being held by the soil, and more drought resilience.  Plowing or tilling lands burns up and reduces organic matter, so it can be counterproductive for water-holding capacity, soil fertility, and tilth.  For weed control between rows, set the tiller to just till the top few inches.

Plants absorb water very efficiently through leaves.  This rehydrates the entire plant.    Plants transpire, which means they lose moisture from their leaves.  Water loss from soil covered with plants is mostly from transpiration of the plants.  The equivalent area of bare soil usually loses much less water.  The more plants you have in a given area, the greater their water demands on the soil.  So a densely planted crop may be stunted from lack of water, whereas the same plants with more generous spacing may have all the water they need.

Overwatering will cause nutrients to be dissolved deeper into the earth.  When water penetration exceeds the depth of roots, available plant nutrients are beyond the root’s reach.    This is more of a problem if using water soluble chemical fertilizers.  With organic fertilizers, the root zone is only temporarily leached until the nutrient level builds back up after further decomposition of fertilizers and/or organic matter.

On less-watered fringes of a garden, grow deep-rooting and tall perennials like raspberries.  Or plant tall pole beans or peas which can catch the dry fringe overspray.  It will then drip off the leaves onto their root zone.

If a drought hits and you are in danger of losing all your garden plants, try eliminating every other plant.  That will give the remaining plants more water and a better chance at surviving and thriving well enough to provide you with some food.

It’s often advised to use tuna cans to measure watering.  It’s better to dig holes to see how wet the soil is.

An elevated sprinkler works well to cover a large vegetable garden.  We used this sprinkler and found that it did a great job and held up for many years.

Plant sunflowers as water status indicators.  They need more water than corn.  When the sunflowers wilt, it’s time to water the corn.

Stakes at the end of rows protect plants by keeping your hoses from dragging over your plants.

Instead of raised beds, consider sunken beds.  They retain moister better.

To hold rainwater, consider swales which are shallow ditches running along the contours of the land.

The USDA cooperative soil survey program has mapped nearly every county and every bit of land in the US.  The information includes soil types, soil depth, available water capacity, limitations, appropriate agricultural uses and management, and susceptibility to erosion, drought, and flooding.  The information is online at http://www.nrcs.usda.gov/wps/portal/nrcs/main/soils/survey/ .

To Drip or not to Drip

Drip irrigation is a way to save water.  Plastic tubes are placed near plants and holes are placed in the tubes near where plants are planted.  Many people find it works well for them.  I didn’t like it when we used drip irrigation for many reasons:

Drip tubes are easily cut with hoes and shovels, and emitter holes tend to become plugged up, so the system needs to be inspected and repaired often.  Drip lines also shift as they expand and contract so they don’t stay on the spot where needed.  Using soaker hoses instead may solve these issues.  Water will disburse along the entire hose, so hole placement isn’t an issue.  And plugged emitter holes aren’t an issue.

Installing the drip system is time consuming.  And then after the system is installed, a few months later the system will need to be picked up for the winter.

The plastic tubes are subject to rodents and other critters moving them or biting holes in them.  Checking for leaks and making repairs is time consuming.

If water pressure is an issue, you may find it challenging to keep plants watered at the end of your drip lines.

The plastic irrigation lines are good for a year in practice, and aren’t cheap.  Roots grow in and around them and weeding will move them or worse, destroy them.

Plants will look dusty and dirty, and there will be no washing away of aphids.  Also, dry topsoil will be blown away in windstorms.

I found the comment below on a forum:

I installed about 3000 feet of 1/4″ inner diameter of rubber drip line. It did not work well, but I didn’t really realize it until we changed systems. What I did know is that my sharp shovels were constantly cutting them (notice I blame the shovel, not the operator). Also, many times, I didn’t know I had cut a line until it caused insufficient water somewhere, and then we would have to chase down a super wet spot and repair the line.
When I changed to overhead sprinklers, my plants exploded in new growth. I thought water conservation and soaking lines were ideal…NOT!
A concern with overhead is water on the foliage. I had bought into that idea, with no experience to back it. After the explosion of growth with overhead watering, it became extremely evident that overhead was superior to soak lines, which had been starving my plants. Perhaps if I had switched to one inch soak lines it would have worked well, but you still have the problem of cutting the lines.
But, back to the criticism of water on the foliage from overhead watering: water falls from the sky, God planned it that way, it’s been working for thousands of years. I rest my point in general terms.

If you are interested in exploring drip irrigation further, a recommended book on drip irrigation is Drip Irrigation For Every Landscape and All Climates.  I like that this book recommends a one half inch drip line as an uncomplicated system that will reduce your effort.