To lessen the maintenance of containers, I have started looking for and buying low water use, heat loving perennials and annuals, plants native and adaptive to hotter dryer regions of the U.S. and the world. These are readily available through catalogs and the Internet, some locally. I thrill to their exotic shape and form, even without flowers. They add an architectural or focal point to a space or garden room.
Use larger containers for less frequent watering. The more drought tolerant the plant, the smaller the container you could use and still enjoy low maintenance. Containers need a drain hole or holes at the bottom, and a type of pot feet to allow the water to drain out. Avoid water logging the roots. The popular lightweight foam or insulated containers work well to lessen evaporation. These insulated containers will allow you to winter over some cold hardy perennials and pansies. Matching plant to container increases visual appeal and pleasure.
When watering, insure the water soaks into the root zone, not just seeping down around the rim of the pot. The drainage quality of your container mix is very important. Sometimes a crust will form at the surface, prohibiting in soak of water. Applying appropriate mulch helps prevent this: pea gravel, crushed granite, lava rock, etc. for drought tolerant plants, or organic mulch for medium (and high) water-use containers. Water twice thoroughly, insuring water runs out through the bottom. If you are not certain water is reaching the root zone (just running down the sides), carefully poke holes in the soil with a thin sharp object; please be careful not to injure the roots.
pH of Water
Our normal city tap water is alkaline (and indeed, well water may be as well). Rain water is not alkaline, but acidic, normally about 5.6 pH. The acidity in rainwater varies, especially when accompanied by lightening, when it can reach an acidity of 4.4 pH. Plants tend to perform better when using water with a slightly acidic pH.
It is helpful to know the pH of your water supply. If city water, they recommend calling your city water department. Another recommendation if you decide not to invest $100 in a reliable pH meter, is to buy liquid pH solution indicators. They further recommend the pH of water be within the 5 to 6 range. Monitor the results (that is, whether a little more may be required for your water supply). They caution it is important not to add too much acid – stronger solutions can burn or damage roots. I recently bought pH test strips at a local pool supplier to find a general pH range for watering plants in containers.
I tested my tap water in Amarillo to see how much vinegar I'd need to add. Our tap water has a pH of approximately 8.0. To lower this to a 5-6 ph range took me 1 tsp for a half gallon watering can, or approximately 3 tablespoons for a 5 gallon bucket (1 ounce of vinegar). Use the plain white vinegar, unless you want to add some nutrients (in which case, an organic apple cider vinegar would be good). I also started to set the 5 gallons bucket in the sun for 2 days to let the chlorine dissipate. This is necessary anytime you use a microbe-based plant food.
Nurseries and some farmers adjust the pH of the water for specific crops to a slightly acidic solution, and some of the cacti literature suggests a pH of 6-7. However these authors feel that is still too high, using the 5-6 pH range themselves.
One can avoid even this minimal maintenance by using rainwater. The Acidic Solutions article in the September/October Cacti and Succulents Journal, talked mainly about watering cacti with acidic water; they mentioned it should apply to other succulents as well. The pictures in the journal showed noted improvement even after only one week. Watering of cacti and succulents is covered in more detail in my Musings section, under an article title: Improve the Growth of Cacti and Other Succulents
Some Plant Suggestions
Many of the non-cold hardy bromeliads succulents and exotics such as crassulas, dyckias, echeverias, haworthias, hectias, manfredas (amoles), bulbines, aloes, agaves, New Zealand Flax and cordylines, cupheas, even palms, cacti and yuccas make excellent low care, low to medium water-use container plants. These are just a few that caught my eye – there are many, many more. My plant selection focused on cold hardiness to Zone 8a, which is an average minimum low temperature of 10-15°. I have found the tendency to save them over winter and am trialing many to see if they will winter over in my unheated shed and garage. Any drought tolerant plant is a terrible thing to waste! So far, this winter of 2005-2006, our official low temperature dipped to -3°. The top growth has frozen off a hectia and manfreda in containers I carried into the shed. I won’t know until late spring if it is root hardy. Plants protected in the attached garage have faired better; their top growth is still viable.
The above mentioned plants did not make it that winter. Since the winter of 2006, I over-wintered these cold-sensitive succulents in my shed with a heater. I've found this to be a low cost method of wintering over container plants. Just be sure the heater is always on! In a power outage, you'll probably have to bring them inside the house and hope for the best! (Added 2/7/09).
Soil Mix for Medium and Low Water-Use Containers
The use of containers also elevates your eye to higher, above ground levels, especially when using wall containers for increased visual interest. Container soil mixes are different for these drought tolerant gems. Grittier for good drainage, with less organic matter as they are frugal feeders, you may want to add a small amount of water absorbing polymers (use sparsely, take care not to rot roots) or water and nutrient retaining inorganic amendments such as expanded blue shale and Turface. As noted throughout this website, these new inorganic amendments also increase drainage, a very good feature for most low water-use, heat loving southwest type plants. This past growing season, watering of my container low water-use, heat appropriate plants became more sporadic and infrequent as the summer passed, without any noticeable signs of stress or decline. I would often go 7 – 10 days at a time without watering. They are flexible; you could water daily if that is your desire, just as long as your container soil mix had adequate drainage for the plant.
The soil mix I start with is two parts garden soil (resembles a nice grade of clay loam from my well amended vegetable garden), one part grit (this could be coarse sand, lava or granite rock, etc) and one part Turface or expanded blue shale – whatever is available. I do not add fertilizers, but I do add a 1 lb. coffee-can size serving of minerals, such as a general mineral blend or rock dust (almost any higher grade brand will do) and Yum-Yum mix, or it’s separate components, whatever I have on hand to a common-sized wheel barrow size of the mix. For cacti, a grittier mix is needed. Most cacti will do well in a soil mix using one part sand, one part forest mulch and two parts pumice or perlite (courtesy of B & B Cactus Farm, Tucson, Arizona).
I will make adjustments to this basic recipe for plants I know deviate from this norm, adding perhaps more garden soil, organic matter, or amendment for drainage as needed. If your vegetable garden soil is not up to loam standards, add more organic matter, preferably good grade compost or composted manure or inorganic amendment for increased drainage. Remember, bag compost and composted manure vary greatly in its quality. Visually check out the contents of the bags before purchasing to insure you are purchasing 100% composted manure or plant product, not fillers.
Asbestos and Vermiculite
Several months ago I received this notice about asbestos in vermiculite from Josh Landon, who is in public relations with Mesotheleoma.com. While asbestos was included in some vermiculite in the past (as is not now), one needs to be aware of older supplies. for more information, please read below Josh Landon's letter and then go to http://www.mesothelioma-information-and-hope.com/Mesothelioma-and-Asbestos.html for more information.
"When we hear the word “asbestos” we often think back on the controversy of the late 1970’s when it became common knowledge that asbestos was indeed a human health hazard. Asbestos however, is still a relevant hazard today in a number of different capacities. While most asbestos containing products were banned by the Consumer Product Safety Commission and regulated by the Environmental Protection Agency, unfortunately it still exists in hundreds of older products as well as in trace amounts in newly manufactured products. Among new products that may still contain asbestos are soil retention enhancers, particularly vermiculite.
Vermiculite is mined from natural deposits across the globe and has a myriad of uses not only for commercial and private gardening, but also as an insulation compound. Vermiculite forms over millions of years due to the weathering of the mineral, biotite. Unfortunately, former biotite deposits are often in close proximity to deposits of diopside, which upon being subjected to the same weathering and age conditions becomes asbestos.
In Libby, MT one particularly mine shipped hundreds of thousands of tons of asbestos-contaminated vermiculite across the country. However, they were not the only manufacturers of vermiculite to ship asbestos with their products. Many other manufacturers were doing the same thing before EPA testing and regulations finally forced them to limit the amount of residual asbestos dust in the vermiculite.
Today, most vermiculite is safe. However, that is not to say it cannot contain asbestos. Vermiculite which is accompanied by a great deal of dust likely has residual asbestos in its contents and should be used with caution. Current EPA regulations ban products which contain 1% or more asbestos. Unfortunately even products containing less that 1% asbestos are still extremely hazardous, particularly when in loose dust form as vermiculite often is manufactured.
It is no surprise then that hundreds of the Libby mine’s employees and residents of the town were diagnosed with mesothelioma, a rare and aggressive cancer that is known only to be caused by asbestos exposure. Options for mesothelioma treatment are limited, so many of these residents were able to secure financial compensation for their families through litigation. Mesothelioma incidence is also known to be high in commercial gardeners and other occupations which deal with large amounts of loose vermiculite.
Fortunately, exposure to asbestos-contaminated vermiculite can be avoided if consumers follow simple precautions. Note the appearance of the vermiculite. If it seems to carry a great deal of residual dust, dispose of it outdoors. Most manufacturers of vermiculite mark their products packaging with “Non Dusty” labels. These refined granules are often slightly more expensive but they are certainly the safest." Josh Landon
Environmental Protection Agency. EPA Asbestos Materials Ban.1989
Consumer Product Safety Commission. Asbestos Consumer Products.