Water-saving products for the garden, Part III
by Linda Coyner
Since I started this series two months ago*, the weather has flip-flopped as much as the stock market. Some areas have gone from drought to flooding and back again.** Parts of the northeast got much needed rain, central Texas is grappling with floods, but many parts of the countryeven those who have caught up with rain amounts are advised to conserve. That's because underground aquifers and reservoirs are being depleted faster than they can be replenished. As a result, water conservation has become a fact of life.
Products that help us conserve water, like those discussed below, will continue to be important, regardless of the weather. More water-conserving products are entering the mainstream, joining those that have been around 20 years or more, in some cases.
Are the new products clutter or worth adding to our water-conserving arsenal? The newest include the Gator bag, moisture sensor, and wrist-operated hose nozzle. I put some of them to work in my garden, observed them in others' gardens, and researched how they worked. Here's what I found:
These plastic sacks look like green teepee around the base of a tree. They're sometimes visible on trees in road medians or in demonstration gardens. They slowly drip their contentsup to 20 gallons of waterover the course of eight to 32 hours. (The flow rate is adjustable.) One bag fits trees with a trunk of three inches; for trunks up to 12 inches, zipper together additional sections to expand the bag's circumference.
Gator Bag works well with newly planted trees. To keep an even level of moisture, however, the bags have to be refilled frequently, which is only practical for the limited period of time it takes for a tree to get established.
The bags, I realized, are no substitute for planting the right plant in the right place. At first I thought I could use the bags to keep a moisture-loving tree happy, but I soon realized that refilling the reservoirs was as much a nuisance as watering with the hose. In such a case, lots of mulch and a soaker hose on a timer would be a better solution. (Better yet, move the tree to a naturally moist location, which I still haven't done.)
Nor do Gator bags work for low branching trees or multi-stem shrubs. Even thought the diameter of the bag can be adjusted by zippering on additional panels, the opening is narrow and the two-foot height of the bag limits its use on shrubby trunks. In my Internet wanderings, I came across the idea of using buckets or plastic jugs filled with water and punched with holes in the bottoms. The problem, however, is that you have to use really big containers to get the water to last as long as a Gator bag.
Gator bags aren't cheap but they're durable enough to last for many years. They cost $23 in the A.M. Leonard catalog (www.amlgardener.com). Treegator Jr., a flat, donut-shaped version for smaller trees, costs $22. I bought my Gator bags at an irrigation business.
This idea has been around for a long time. A lot of water runs off a roof and these barrels work with the downspout to collect some of it. Most have a spigot that makes it easy to water plants, especially if you place the barrel on a raised stand so that gravity works for you. Make sure your barrel has mosquito netting or screen. A secure lid is even better as it keeps kids and critters out.
A diverter for the downspout is essential. This neat gadget directs water into the barrel until full, at which time the water backs up and forces the diverter to direct the water elsewhere.
A barrel that holds about 60 gallonsand includes a childproof lidcosts about $100. A fancy diverter costs about $20 at envirocare.net , but there are more basic ones are less expensive.
There is a cheaper alternative and, no, it isn't a trash canapparently trash cans aren't strong enough and can collapse under the weight of the water. Jumbo plastic barrels made for shipping, however, are worth considering. They cheap, usually less than $10 I've read, and sometimes turn up at garage sales. If you do go that route, make sure you find out what the barrel was originally was used for. Some barrels may have been used for shipping toxic chemicals.
Some environmental groups and municipalities sell rain barrels at subsidized prices, I've heard, in much the same way as they offer compost bins for sale. For used shipping barrels, check with a local food distributor or shipping company. For more information, see www.h2ouse.com
The GreenWell looks like a hollow plastic donut cut in half horizontally. It acts as a reservoir to retain moisture and deliver water to the root zone. When plants and trees are planted on a slope, the collar keeps the water where it will do some good, not running down the slope along with the topsoil. A thick layer of mulch also does the trick, but with less precision.
GreenWells are priced four for $44. http://www.envirocare.net/greenwell/ordering.htm
Rain sensors are now required on irrigation systems in many areas but have their limitations, witness all the sprinklers running while it's raining. A rain sensor simply overrides a watering system once a specific amount of rain has been collected. It also resets the sprinkler system for normal operation when the turf requires more water. It seem like the perfect solution but faulty installation, wildlife and leaf debris make many inoperable. Still, even perfectly operating rain sensors are smart enough to take into consideration temperature, humidity, cloud cover, or wind, factors that can affect the moisture a landscape needs.
A new product called a moisture sensor has the potential to reap water savings while keeping the landscape evenly watered and, hence, healthier. The moisture sensor measures the moisture in the soil via a probe that relays the information back to the irrigation system's controller. When moisture drops below a set amount, the controller activates irrigation, automatically superseding scheduled watering cycles. The only problem I foresee is that the probe is measuring the moisture content in only one location, so it would be important to pick an area that's typical of your yard in exposure and soil type.
If you've ever left a sprinkler or a soaker hose on all night, consider these easy-to-use and affordable devices. They can be high-tech electronic devices or simple mechanical timers, the latter being my preference. Either way, they shut off automatically when time's up. It's still a good idea to turn the faucet off as soon as you get a chance. Electronic timers range from $60 and up. The mechanical Gardena G1169 enables you to set watering times between five minutes and two hours. The Gilmour 9200 lets you set times up to 4 1/2 hours, which works better for a soaker hose. It can also set gallons.
When you do use a hose, use one with a nozzle that can be shut off when not in use. For those who find it inconvenient to use a nozzle's off switch, many brands offer a range of trigger-based sprayers that only spray when the user positively engages either a trigger or button. This means that 'off' or 'no flow' is the default setting.
Another approach is the ergonomic spray gun offered by www.rittenhouse.ca The nozzle looks like a soft, straight rod. It has no trigger or button to turn it on. While gripping it, you release water by gently bending your wrist. To shut the water off, release the nozzle. The spray pattern is adjustable.
It sounds like an oxymoron, but it's water in a solid form made of a mixture of water, food grade vegetable gum, and alum. When it comes in contact with soil, the gel slowly returns to water. For outdoor plants, slice off the bottom of a quart-size cardboard cartons and bury it on a slant in the top of pre-moistened soil. The jelled mixture beings to drip water to the plant roots once it comes in contact with soil bacteria, penetrating 15 inches. The manufacturer promises that it will release water for 90 to 100 days.
Depending on the size of the plant, you'll probably need several cartons. For smaller plants, in sausage-shaped tubes of the gel are placed on the soil surface. One 9-ounce package is supposed to provide a plant with a continuously for 30 to 60 days to a depth of 5 inches. The product is likely to be a solution for long-term watering for hard-to-reach plants on the patio or in the house and for new plants in the garden. Another use would be to water plants while on vacation. My only concern would be that by keeping the top five inches of soil moist in a potted plant of any size would encourage the plant roots to concentrate in the top of the pot. Driwater quarts are priced less than $2.50; the tubes are about $1.50.
*Garden Edition: June 2002, Water-saving products for the garden, Part II: Superabsorbers
Garden Edition: May 2002, Water-saving products for the garden: soaker hoses