Square foot Gardening for the north – A Primer
Square foot gardening to me is a method of small area, high yield, low maintenance gardening. Some say it is perfect for beginners and less mobile individuals however it is perfectly suited for small urban area gardens springing up around the country. The faster heating up of garden boxes as opposed to standard garden rows also makes square foot gardening ideal for northerly climates.
Square foot Gardening (SFG) utilizes raised beds with deep soils blended to the specific plants housed within. The raised beds are divided into square foot areas (hence the name) and each area is assigned a specific plant with its own “plant spacing” requirements.
Some Useful Reading on square foot gardening:
Plant spacing’s in SFG are more tightly packed than the traditional garden. This serves three useful purposes:
- Allows more crop per area and at the same. (less area, less fertilizer)
- Increased density/foliage holds moisture in. (less area, shaded, less water)
- Dense foliage hampers weed growth. (less competition, less water and less fertilizer)
More crop per area
The plant spacings are made assuming minimal plant spacing and maximum water/food availability. A traditional bush bean spacing is eight to twelve inches in a row whereas SFG allows nine per square foot.
Why such tight spacings? Easy, with proper well turned and deep soils roots will grow down deeper and not spread laterally as much as in rows. With the tight spacings, plant bases are shaded more and as such more water is retained in the soil. Weeds tend to be overwhelmed by the densely planted vegetables and don’t rob them of as much nutrients.
Raised beds tend to be confined to wooded frames although any method that allows the bed to be raised above the surrounding topography is good. Beds should be 4 inches to 12 inches above the topography. Woods used should be untreated with rough cut cedar being the best but untreated spruce 2×6’s do the job nicely and should last 5 or 6 years before they rot to much.
The largest box for a raised bed should not exceed arms length from any side so an established 4×8 box seems to be the largest for proper plant access/working. Spacings between boxes should allow for easy movement between the boxes while allowing overflow space for some of the more leafier plants. Walkways of 1-4 feet are common and should be maintained (trimmed grass, crushed stone, mulch etc) to discourage weed growth.
Soils for SFG need to be rich in nutrients, able to retain water and deep. Nutrients are obtained and replenished via composts of various sorts as well as occasional fertilizer additions if necessary (to much fertilizer results in lots of greener, no so much vegetables). Water content in soil can be helped by the organics supplied by regular composting however supplementing with peat moss in moderation can be highly beneficial. Soil should be well worked and loose down to at least 6 inches with 12 inches being ideal for most plants.
Plant spacings are tried and true at this point in time with numerous resources (Google: square foot gardening plant spacings) available. Customizing the plant spacings to you’re specific soil/area maybe necessary but don’t be alarmed by the very tight plant spacings.
Since plant spacings are all based on a single square foot, any size or shape is possible under square foot gardening rules. The plant spacings and growth habits will dictate where the ideal planting location will be (tall plants on north side, vining plants on edges, etc.). << Click here to view north hardy plants >>
Adding a third dimension to square foot gardening allows for an even more productive/cleaner SFG. Traditional vining plants (squash, cucumbers, peas…) tend to take up a lot of horizontal area – even in a standard SFG squash/cucumbers are planted on outside edges as the vines will get quite long and could overwhelm smaller plants if allowed to grow within the SFG.
Peas and pole beans tend to be aggressive climbers and will easily grow vertically up just about anything. Although peas tend to grow 6-7 feet, pole beans can get twice that height so take that into account when designing something for them to climb.
Cucumbers grow vertically as well, not as aggressive as peas and pole beans and a height of 4-6 feet is usually sufficient around my area. For cucumbers I utilize a net trellis and will tie up the vines as they grow.
The vertical nature and heights of these plants trellised will cause shading of other garden plants and should be accounted for in their placement.
Squash and Pumpkin can be trained up net trellises vertically however I have found it easier and more natural for them to climb a simple net trellis at an angle (45-60 degrees). This will put less strain on the stems holding the fruit and keep them off the ground. by zigzagging the vines up the trellis you can get a 30 foot vein to easily fit on a 4×6 mesh trellis.
Square foot gardens, due to rich deep soils and plant density retains allot of water with little lost to evaporation compared to traditional methods. As such watering is done less often and with less water per watering session. Usually i water every few days with 1/2 to one inch of water per session. Water hogs like squash, cucumbers and tomatoes may get more if they look like they need it.
Fertilizing is done in the fall after all the plants are harvested or in the spring before planting. Addition of rich composts collected over the winter or purchased is essential for the nutrient draining effects of high density planting. In addition I utilize a liquid fertilizer in moderation every few weeks although I am certain it isn’t needed. If your plants are growing a ton of foliage and no fruit/vegetables then you are utilizing to much fertilizer.
Weeding during the early stages of growth is essential and as the plants overcrowd potential weeds out it becomes less and less of an issue. Large and deep root weeds should be removed when found as they can outgrow the vegetables at times.
Growing in the North
The raised boxes allow for at least two distinct advantages over traditional growing methods. This first being that raised beds tend to heat up and defrost faster than the standard row in ground gardening.
In addition, the small standard box sizes allow for quick and easy setup of covers to turn individual boxes into mini greenhouses with a little lumber and some plastic, further extending the planting season.