Mid-August to the end of September are cool-season planting times in the Southwest, depending upon the crop. As you plan your cool season garden, consider garden location and microclimates and how they affect the growth of your plants. As in real estate, plant growth is more about location than any other gardening element.
We tend to think of garden light as it falls on our house: north/south/east or west-facing. In the Southwest, east-facing gardens are best for the warm season because west walls shade the garden from the hot afternoon sun, and in colder states, a west-facing garden is best in order to capture that same warm sun.
For the Southwest, things change in the winter or cool season months and we want what other states have: west-facing, warm sun, but west sun in the summer will burn our crops and end the growing season prematurely. It’s complicated if we want to grow both warm and cold-season crops.
A great way to check the movement of the sun in your backyard everyday of the year is the Sun Seeker app (Apple itunes and Android Google Play). It not only tracks the sun at your specific location, but you can call up a 3-D or street level view and see how the sun moves across your property or almost anywhere in the world. (Video showing capabilities). I bought the package, which includes Moon Seeker and Wind Seeker. I get terrible winds during our monsoon season that have knocked down crops, so I use it to monitor what direction the winds flow. I can prevent some of the damage by providing barriers. So your first step is to figure out your general climate in the garden area, then map out your current microclimates. If you don’t want the app, you can always take photos early in the morning, at noon and late afternoon to see the movement of the sun.
Plants require a minimum of six hours of direct sun a day and, depending upon the plant, grow best with 12 hours. In most cases, that means full sun for cool season gardens and full sun for about 8 hours in the warm-season garden, then about 4 hours of diffused light during the hottest time of the day.
Microclimates change everything but done well, they can give you the best of both worlds for warm and cool-season gardens. A microclimate is a small, defined area where the climate is different from the general climate surrounding it (think controlled shade or wind). A wall near a garden, if it casts a shadow, creates a microclimate. So do trees, structures and other natural and man-made barriers. For example, to create the perfect warm and cool-season environment, a deciduous tree, planted to shade a garden from the burning west sun in the summer will allow full afternoon sun in winter as it sheds its leaves. The same effect is achieved through shade screens. Most barriers or trees will provide shade equal to their height when the sun is at its peak shade level (low on the horizon).
To plan correct placement of your garden or create the optimal space through controlled microclimates, photograph your yard or use the app, sketch it out on paper then outline the microclimates and color shaded areas at peak shade level. Once you have done that, analyze the best placements and plan future natural or manmade barriers that will create the ideal microclimate for your planting area.
It’s important to plan your plant placement according to the microclimates. For example, lettuce, kale and many herbs handle as little as 6 hours of sun. Strawberries, peppers and tomatoes require full sun with diffused sun protection against the west sun once temperatures rise above 95 degrees. About 95 degrees is the magic number because at this point, most plants begin dormancy to preserve water. Shade will lower temperatures and extend the growing season. Seed packets and plant tags will tell you whether the plant needs full or partial sun.
The second most important consideration is how close your location is to water. The closer the water is to your garden, the more successful it will be because it means less work for you. The best option for the Southwest is drip or automated watering (see June 27, 2016 blog on watering). Even then, you need to know where your underground water lines are if you want to tie into them.
Choose your location carefully and you will reap maximum, quality harvest as each season progresses.