This year most of Alberta has had a longer period without frost, and many areas have been lucky enough not to be hit yet, and it’s nearly October! Well if you are looking for ways to dodge the first few days of frost when they do happen, here are some options-both obvious and maybe not so obvious (and if your garden has been hit, start planning for next year).
Frost generally occurs for two reasons:
1. Either there has not been enough heat accumulated throughout the day or
2. The heat that was accumulated has been allowed to escape to the point the temperature drops to freezing.
Drop Cloth—for a simple “Band-Aid” solution, the old standby, quick-fix is the drop cloth. Use any old bed sheets or blankets and make sure not to break any fragile branches. Placing stakes into the ground every few feet is a good way to keep the branches safe. This can work for fruit trees as well, depending on size. Remember to remove each morning after frost danger has passed.
Mulch –Although not really a viable solution for protecting tomatoes or other large annuals, mulch is an option that prevents the escape of heat into the atmosphere and would generally be used on plants less than six inches in height, or to protect roots of perennials over the winter. In addition to preventing water loss, it acts as an insulator. Good mulches for autumn include leaves and other organic debris.
Water—Water acts as a temperature pacifier and keeps the ambient temperature from fluctuating as much as it otherwise would in drier conditions. The key here is to ensure the temperatures at the time of spraying are not already close to freezing. Watering near or just before the warmest part of the day is best as long as most of the water does not evaporate before nightfall. Another idea is to use water that sits in a rain harvesting system that has been sitting in sun for several hours. Just be sure not to shock the plants by any sudden temperature changes when first spraying.
The following may be too late to start implementing this year, but these are some you may contemplate for future seasons…
Heat sinks—A heat sink is any physical body that collects the sun’s radiation throughout the day and releases this captured heat after dark. Such examples include large rock or brick masses, water tanks, and anything especially dark in colour. Remember that the effect can vary greatly depending on the type of material used as well as its colour. Experiment and do your own research.
Elevation—the areas especially prone to frost depend on elevation. So which is it, the higher areas or the lower areas? Well, both actually. Cold air tends to sink to the ground and ‘pool’ at the lowest spots as if it were water. At the same time, areas on the peaks of hills are more exposed and the soonest to fall victim to cold air masses. So the best answer is whenever possible, plant the most tender plants in the mid-elevations. They will be protected by the higher surfaces and most of the coldest air will sink to the lowest spots first.
Planting under a frost barrier—Finally, planting larger and less frost-sensitive plants and trees in such a way as they shield the lower plants from heat loss is an excellent way to keep the ground temperature from dropping to freezing. The general rule that works best here is, the less of the night sky that is visible, the less heat will be lost. Conifers or any tree with broad, over-hanging branches are good options. Just ensure that they will not shade out the plants, so planting these taller trees on the north side of fragile lower plants is a good solution.
Finally, many root vegetables such as carrots, parsnips, turnips and so on can be kept in the ground for several frosts. Some say it actually enhances flavour. For extra protection, simply cover in a six-inch layer of mulch and in Calgary's climate, this should suffice for well into October.
Remember that it only takes a couple of hours for frost to cause damage. iin most cases the best we can expect is about a few degrees maximum that we can affect the temperature. This is done by collecting the sun’s energy during the day and making sure it stays with the most sensitive plants at night. Sometimes though this can make a huge difference when the autumn sees just a hand-full of days that hover around freezing, followed by a couple of weeks of warmer nighttime temperatures. So take advantage of the longer growing season with these few simple measures against frost.
Passive Solar Greenhouses
Permaculture Tour 2012 is Here
Plant Polycultures-A Garden with Many Functions
When designing a food-bearing landscape, one of the first things to decide is what plants will go where in the growing space. Most of us have heard of companion planting, square-foot gardening, perennial food forests, and inter-planting. Creating a polyculture combines many of these strategies and more. In this issue we will look at the planning stages of a polyculture and the elements necessary in creating a resilient and productive one.
In books and all over the internet, we can find loads of advice on which plants grow well together and which ones do not. Some of these combinations work fairly well, while others have yet to convince me. Providing mishmashes of different vegetables is not our purpose here. Since climates, pests, soil types, and our own tastes vary, we want to discover what works well in our own gardens, and we can do so by choosing plants not by species, but via the function they perform in the landscape.
Keep in mind that perennials are very useful in a polyculture. We can plant only annuals, but this is asking more much more work in the long run. Here is a list of functions (not necessarily in order of importance) that we want to include in any polyculture. A quick web search under any of these topics will provide numerous plant types suitable for any garden. If we have balanced proportions of plants in each of these categories, we are off to a good start:
A. Nutrient Accumulators
The thick and/or long roots of these species plunge far into the earth to extract minerals and other ingredients necessary for all plants to thrive. Usually after several of these species have matured, they will begin a natural decline in numbers once their job is complete. Examples of these might include: plantain, alfalfa, dandelion, chicory, and mustard species.
B. Nitrogen Fixers
In any guild, it is crucial to have plants that fix nitrogen in the soil. These plants have a specialized ability to extract nitrogen from the atmosphere and place it into the soil. Nitrogen is a necessary element in all plant development and speeds the growth of all plants. Nitrogen fixers include plants such as clover, peas, potatoes, Siberian pea shrub (caragana arborescens), lupines, and any leguminous or bean type plant.
C. Mulch Plants
We use these plants for building soil, preventing erosion and evaporation, and protecting and shading the roots of others. In this category we often might include a process called “chop and drop”, which involves cutting the plant down at the soil surface and leaving the greens on the soil to eventually decay. The roots either come back as another plant, or decay as well becoming part of the humus layer of the soil. The “chopped” parts of the plants also become a thick and fluffy layer on top of the soil. Some examples for mulch plants are rhubarb, nasturtiums, Jerusalem artichoke, mustard, oats, and barley, and virtually any soft-leaf plant that decomposes quickly.
These are any plants that will attract beneficial insects to your site (insects that will either pollenate to produce fruit or will consume/deter pests). Insect attractors include dill, coriander, thyme, yarrow, fennel, and believe it or not, dandelion.
There are other smaller categories, such as those which provide animal habitat and those which act as soil fumigants, but beginning with the four listed above is a good start.
Additionally, it is wise to use any plant that is able to perform more than one of the above jobs. This is what we call ‘stacking functions’. Examples of this would be using clover as both a mulch plant as well as a nitrogen fixer, or growing comfrey as a nutrient accumulator and to fix nitrogen or even using rhubarb as a mulch plant and of course a human food.
Finally, we should keep in mind the actual space each plant takes up in the landscape—both above ground and below. This is why we try to arrange plants in a polycultured landscape, creating a ‘mosaic’ in which generally we keep similar plants away from each other as much as possible. Doing so will minimize competition for sunlight and soil, as well as confuse pests (or at least keep them confined to one or two plants.) As in any form of permaculture, the more functions we can cover off each time, the more resilient the system and the less energy it will consume in the long run.
Passive Solar Greenhouses Beginning to Appear in Calgary
Many people protest the short growing season in Southern Alberta. With some techniques such as raised beds, cloches, and mulching, we can usually expand the less than 110 frost-free days, but some people are taking things a little further. A passive solar greenhouse can expand the growing season by several months without the use of external power. Unlike traditional greenhouses, the idea here is to trap solar radiation within the structure to create the appropriate growing conditions for most plants. So how is this accomplished? Think of what happens when we leave our vehicles parked for a while on a sunny day. Even on a day reaching a mere 15 C, the interior can be quite hot. This is because the glass allows the solar radiation to enter, while the rest of the car absorbs this heat and insulates against heat loss. Most greenhouses lose heat through any side of the structure that faces away from the sun. What we are trying to accomplish with the passive solar type is to minimize heat loss. To do so, the north and sometimes east and west sides are built with walls containing good insulating materials—sometimes with an R-value greater than most homes. On the opposite end of the scale, adequate ventilation is a must especially for the warmer days of summer. There are many other modifications that can be made, such as the angle of the glass and materials used as well as covering the whole structure with insulated blankets in the coldest days of winter. Nevertheless, experimentation with capturing and holding heat and moderating temperature so that plants might one day make it through our severe winters, continues. The following are links to a couple that have popped up in Calgary. (I also have a friend (no link yet) who has just installed a solar heated shower in hers).
Verge Permaculture, Just completed the addition of a rocket stove to this one…
This one by Joshua Baker of Radicle Routes was constructed using reclaimed materials…
Calgary Permaculture Tour 2012 is Here
For those not already in the know, on Sept 1, 2012 Prairie Sage will be conducting a one day tour of Calgary's most prominent and exciting sustainable and regenerative living sites. Details of the day are as follows...This excursion will be both educational and fun! Leave your vehicles or bicycles at our meeting place (The AREA 12:30 pm) and be escorted around Calgary for a tour of such notable places as Verge Permaculture, Patterson Springs Farm, The AREA and more. The tour will conclude in the evening with a locally brewed wine/mead and dinner at the AREA in Inglewood. More information can be found HERE!
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Ted Bahr is the founder of Prairie Sage Permaculture. MORE