We recently posted an article on how the soil in raised garden beds gets hot in certain situations. That article got us thinking about our choices while placing the raised garden beds where they will permanently sit and how this can be affected by the sun during the day.
We will all face this choice, so we thought we would offer our thoughts on the topic after a few years of growing almost all of our own vegetables on site in these very same garden beds.
We are close to being self-sufficient in vegetables, and we are in fruit and table greens. Because of this, we feel we are qualified to share thoughts that have some meaning to them.
If you are considering metal raised garden beds, the following information might be helpful. If you have narrow beds, getting them right can be even more critical; as discussed in how wide should metal raised garden beds be?
What are the pros of an east-west orientation for Raised Garden Beds?
This design is where the end of the garden bed faces the rising sun. The opposite end receives the evening sun, but it is never that simple because we all have different aspects with the rising and setting sun, which depends on your location.
The main pro to this type of garden layout is that there is less shading out of sun-dependent plants from taller plants in the same bed during the day. This shading will occur at the beginning of the day when the sun rises, but this effect diminishes once the sun is higher in the sky.
What are the cons of this garden bed layout?
The main issue we found (because this is how our beds are aligned) is that the most prominent face of the garden beds faces the sun during the hottest times of the day.
This can considerably affect soil temperatures near the side walls of these beds. “Does the soil in metal raised garden beds get hot?” shows what we mean because we ran a test with a thermometer to prove that the hot spots are large enough to warrant planning against.
Does having the garden beds north-south cure this issue?
Because the garden bed wall cops the heat on one face only during the hottest part of the day, if the bed is placed east-west, only one section of soil gets the heat.
With the garden bed facing north-south, both long sides of the bed get the sun but at different times, one being morning and the opposite in the afternoon.
If you live in a warmer climate, you effectively roast your garden soil from both sides during the day. To understand this comment, click that link on soil getting hot. (It opens in a new tab)
Suppose your metal raised garden bed is 3 feet across, and the sun hits both side walls during the day. In that case, you can heat up as much as 8 inches of the soil (2 x 4 inches) with 5 degrees extra heat, which is about 20% of the garden bed growing area.
This temperature rise is likely harmful to the soil micro-organisms that feed out vegetables. It is also very likely to harm the roots of the plants.
This heat issue is usually related to the corrugated steel type of beds. To see if they suit your site, “Are metal raised garden beds a good investment?” might help with some information. For alternatives less susceptible to heat, “What is the safest material for organic raised bed gardening?” can help.
Now, remember this, this is very location specific. In some colder climates, orienting the garden beds to capture the warmth can be a good thing. Hence, they catch the midday sun as much as possible, which makes sense, but this is less applicable as you move toward the equator, where the sun has more bite.
What is the best hemisphere for growing vegetables?
During the permaculture design course, one part of the discussion was on the ability of those in the northern hemisphere to grow vegetables at a far larger size and quantity than we can here in the southern hemisphere.
The soils in the north are generally more fertile, the rainfall is more consistent, and the daylight hours are longer. All of these components go towards helping grow reasonable quantities of food, and maybe this is why the largest populations of people on the planet are in the northern hemisphere.
We live in the tropical zone of the southern hemisphere. The southern soils here in Australia are too poor to support large numbers. We learned how to adapt and get by, and while there are downsides to poor soils and the heat, we appreciate the many pluses.
Consistent fruit supplies are one good start, as well as table greens throughout the year. This is more likely when you transition traditional vegetables from the northern hemisphere to a more Asian style of food.
Is the sunlight different between the two hemispheres?
No, the sunlight on the southern side of the equator is the same as the northern sunlight. Any differences that might be noticed are likely to be location-based because the land masses in the north are more extensive and further from the equator.
This can give a softer light, mainly when the location is closer to the pole than the equator, due to the distance from the equatorial zones being more than the sunlight.
Is morning sunlight better than afternoon sun for growing vegetables?
The early sun is gentler on softer leaves typically found on commonly grown vegetables.
There is a strong recognition that this is the case, and it certainly seems that the early sun is softer than the midday heat. This is likely due to the sun’s distance from your location at sunrise.
The same might be said for the evening sunlight; however, the day’s heat still lingers and can add to the ambient temperatures.
Do sun angles matter with growing vegetables in Raised Garden Beds?
Sun angles matter when you grow food, no matter where you are. Having the garden bed orientation facing the wrong way can cause many problems with soil heat, but this is not the only component of this topic to consider.
Every season brings a different sun angle, presenting opportunities and potential problems we must design our gardens around. This is where a good garden design can be of great benefit, and it starts with “Sun mapping your yard (how this fits into self-sufficiency. “
So now you should be a little more informed on how the direction your raised garden beds face can be beneficial or a problem depending on where you are in this world.
We suggest sitting and thinking about the information above for a few days before jumping into placing your garden beds because they are a pain to relocate. We have two that need to be moved, and we are not looking forward to it.
Article by Tim Blanch for TheTropicalHomestead.com. He is a qualified Permaculture designer.