Square Foot Gardening: Step 3, Pickin' and Gridding

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In this installment of the on-going series of adventures in Square Foot Gardening, we will discuss what plants to plant, how to plant them and how to divide up the planting boxes to plant according to Mel Bartholomew’s method.

What to Plant 

Instead of browsing the seed catalogs and picking out things that look interesting, I suggest you start deciding what to grow by consulting your grocery store receipts.What fresh or frozen produce do you buy regularly?Which are the most expensive?Use this information to pick your Top Ten or core crops list.Add to that when we get to the companion planting step.

How Much Space? 

Each 4 foot x 4 foot planting box is divided into 16 not-quite one foot squares.In each square you will plant one type of vegetable or herb, how many go into each square depends on the size of the plant.

Large plants like tomato, peppers, cabbage, broccoli, cauliflower, and squash will take up at least one full square.Medium-large plants like leaf lettuce will plant 4 to a square, medium plants like spinach and onions will plant 9 to a square, and small plants like carrots and radishes will plant 16 to a square.


Some plants, like squash, will vine all over the place if left to do what they want.But they can be “trained” onto a trellis so they grow vertically instead of horizontally, then each plant needs only one square.Tomatoes too can be pruned to bush out or vine up onto a trellis.

When using a trellis, make sure you set it up on the back side of the box (farthest from the sunshine) so the trellis does not shade the rest of the plants in the box.I’ll talk more about building the trellis’s later, for now, just decide which ones will be trained up a trellis and where they will need to go.

Companion Planting 

Some plants offer extra advantage to other plants when they are grown in close proximity to one another; some offer beneficial nutrient exchange, some repel pests that the other are susceptible to.A great companion planting chart is available from Golden Harvest Organics.Or if you are using the excellent Grit Garden Planner, information on companion planning is included for each vegetable and flower in the Info windows. Use this information to buddy up your crops.

Arrange by Height 

As with the trellis, low-to-the-ground crops need to be in front of taller crops so all get their fair share of sunshine.

Armed with all this information – and how many boxes you have, you can decide how many crops you can grow, and how much of each.

Remember too that you can re-use squares two or more times each season.You might put 16 radishes in one square early in the spring.They mature quickly, when you harvest them, plant carrots.When those are ready for harvest, plant spinach for a fall crop.In this way one square can produce multiple foods.

Stringing the Box 

The Square Foot Gardening book shows the boxes divided up with strips of thin wood making the grid.This looks nice, but takes up more room and seems like they will get in the way when I have to add more soil components and mix them in next spring.So I used nylon string.This string should not rot way too quickly – it should last one season anyway – and replacing it next year will be simple and cheap.

If you made marks on the box sides as you built it, your nail locations are already set.If not, locate the center of each side and drive a 1¼” exterior grade box nail (large head) so that about 1/4″ remains sticking up above the rail.Now divide the space between these center nails and the side rail in half and drive in nails at each location.You should end up with three nails in each side, equally spaced.One last nail goes in a corner – be careful not to hit the nails or screws holding the corner together.

Now find the nail that is diagonally across from the corner nail and tie your string to that nail securely (green X in the drawing).Then run the string directly across the box to the nail opposite the starting point.Pull the string taut and wrap it around the nail a couple of times to help keep it taut.Then hop over to the nail next to where you wrapped the string, go around that nail and back across the box.

Wrap your string around that nail, hop over to the third nail on that side, round it and back across the box.

Now, use the corner nail to get you around the corner and to the first nail in the adjacent side, wrap the string around the nail and shoot across the box.Use the same shoot across, hop down shoot across pattern to run the strings at 90° to the first set and complete your grid.

When you get to the last nail – which will be just around the corner from where you started, tie the string to the nail securely and cut the string loose from your spool.It should now look like this.

Setting Out Your Plants 

I highly recommend making a planting guide for each of your boxes.In the appendices of the All New Square Foot Gardening book is a handy grid that can be photocopied and used for this purpose.If you don’t have the book, just draw one out on paper for each box.Label each page with the box number and which side of the box faces north (or your house or the creek or whatever you use as a landmark) then pencil in each crop name and the number to be planted in the square.

If you have been sprouting seeds indoors as I have, set your seedlings into the soil.If starting from seed, plant the seeds according to the planting charts and put a check mark or date in the square so you know the seed is in.You may want to stagger plantings.Planting a square of radishes each week (or two) will mean you will have 16 fresh radishes coming out each week (or two) all through the season instead of having 80 radishes coming out all at once.Same with lettuce.Neither crop can be preserved, both are used fresh.Most other vegetables can be canned or frozen.

Labeling the square as having been planted, with what and when, helps you to avoid accidentally planting something else there, as well as knowing if something happened to your seed.If germination should take 7-10 days, it’s been two weeks and there is no sign of sprouts, something may have happened to your seed and you may as well plant something else there.

Reserve squares (or plant quick crops like radishes) for the plants that have to wait for warmer weather.

If your boxes are going into a former garden area, like mine, you will want to lay in some straw, stone or pavers around the boxes to help keep you out of the mud when working the garden after a rain.If you plunked the boxes down on top of a lawn, this should not be a problem (you DID leave enough room between boxes to mow didn’t you?).

That’s It

Except for trellis’s, which I will cover next time, that is about all there is to setting-up a Square Foot Garden.Mr. Bartholomew’s book goes into great detail about the details of planting and the appendices offer charts, and tables that are chock full of info.I will drop a progress report in here now and again just to let you know how it’s going and to discuss what worked and what didn’t, but this is almost the end of the how-to part for this series.

I will mention that not all of the vegetables I’m planting are going into the boxes.I have potatoes, corn, cucumbers, bush beans, watermelon, and added tomatoes, peppers, and squash that will go into the ground.

I am looking forward to a bountiful harvest as the season progresses, and I wish you the same.

Thanks for dropping in, feel free to toss your 3 cents worth in below.But first, here’s a demo of the Grit Garden Planner and the way it can be used for Square Foot gardening as well as traditional gardening.I’ve found it to be a great help in so many ways.

Square Foot Gardening: http://www.youtube.com/growveg#p/f/8/dzrNbcW5xZ0