you missing several important point of the method such as the soil fertility.

"I have one 20' foot row; the spacing on a packet of bush beans says 4"-6" per plant. So since you do 9 plants per square foot, would I just divide the 20' row into twenty
12" x 12" squares, then do 9 plants per square foot?"
what you are describing is called wide row gardening.

As for reason for squares it has nothing to do with the space of the gardening it is a graphic device to organize
the garden.
I would comment further but I think it might beyond your comprehension level.

Look I have very little experience with growing stuff in a plot; I didn't even know there was a method called wide row gardening.

You didn't even answer my question; all I want is a simple yes or no answer and why it is or isn't feasible (by feasible I mean possible)

This is under the assumption that the plants are getting adequate sunlight, being well watered, and grown in fertile soil.

I can't tell you how fertile the soil is because I don't know myself.

Sorry you got a rude response. To answer your question if you had highly fertile soil it should work. With high insesity gardening, Square Foot Gardening is a brand name for it, the reason you can put so much so close together is because the soil mix is mostly organic matter. In a plot unless you heavily ammend the soil your spacing will have to be more spead out.

First, you are missing the point of "TRUE" square foot gardening, (SFG). The concept of SFG is to save space, water, fertilizer, and time by focusing all the things plants need in one small place. The SFG concept also uses raised beds to help the soil to drain better and warm faster in the spring.

My garden is 70 feet long by 25 feet wide. I do not use the "TRUE" SFG system, I just divide the garden into 70 foot long beds that are 3 feet wide with an additional 2 feet between the beds for walking. I know that those wide walk ways may see like a waste of space, but since I do not water or apply fertilizer in the walk paths, I think it is still efficient use of the garden. I do not ever walk on the beds, so that soil never gets packed down. The 3 foot wide beds are narrow enough for me to reach the middle easily from one side or the other.

On plant spacing within the beds, I use the spacing from the SFG charts with some modifications. I allow a bit more space between plants. For bush beans 4 to 6 plants per square foot is about right, and since my beds are 3 feet wide, I would have 12 to 18 bean plants for every foot of bed. Make sense?

On the subject of beans, a better approach is to grow pole beans on towers. No more bending to pick the beans, and they stay cleaner. The dirt does not get splashed on them during rain storms.

Kawa; Yes I have done it with my plot. Leave room for yourself to tend the plants. Where I live extra water is required compaired to wider spacing of plants or rows.

Curt

Thank you for the advice and suggestions given, and taking time to post on my thread.

Not to be rude, but to clarify, I don't want to use the entire square foot gardening method. I just want to use the spacing guidelines for it.

I basically plan to use my plot for growing squash and melons in the summer, and in the fall (after the squash and melons have finished growing and have been harvested) for
root veggies.

With a 20' x 20' plot I know really won't get that much more of a yield with melons and squash, but I know I will be able to get a better yield with root veggies using square foot gardening when you compare it to conventional spacing with the traditional layout of a plot in the ground.

I plan to fertilize the soil with a dry 3-4-4 fertilizer; the entire plot will be fertilized with this. I'm a bit confused as to what is meant by 'fertile soil'.

I mean I know what fertile soil is, but I don't want to overfertilize, which apparently is possible and can do more harm than good, and be more of a hindrance than a help.

I'm wondering if I apply fertilizer via tilling it into the soil, then apply fertilizer on the surface of the soil when the plants are older via a water soluble fertilizer, will this be overfertilizing?

I read an article that says for long maturing plants such as squash and melons, you need to apply fertilizer, later in the growing season. Is this referring to the growth cycle of the plants being grown?

Example the variety of butternut squash I have takes about 75 days to mature, so would I apply fertilizer about 37.5 days into it's growth cycle?(this is half of it's maturing cycle, under the assumption it actually matures on time)

I have plenty of water and fertilizer. However space is at a premium; I only have a 20' x 20' plot.

The whole point
I want to do square foot gardening spacing guidelines is to maximize the small amount of space I have, thus getting more harvests and more yields in a smaller amount of space, which supposedly is one of the main reasons for doing an SFG
garden isn't it?

This sounds huge, but when you grow things such as squash and melons, it really eats up your space quickly; this is what I plan to use my plot primarily for. I realize since you can only grow 1 squash plant per square foot.

I plan to use the square foot gardening guidelines for things that aren't as fussy about being grown closer together such as root veggies, leafy green things, etc.

I realize with the leafy green things in comparison to root veggies, even with square foot gardening, you won't get as much bang-for-your-buck (that is the yields won't be as heavy) even implementing square foot garden spacing simply because they require more space, even when spaced closer together.

I realize that although bush type melons and squash with short vines, although they're more tolerant of being grown closer together, and in confined spaces, they really will grow best if allowed to sprawl and have lots of space.

When space is at a premium, the SFG method uses trellises to grow the vining crops up and off the ground. I don't see why a trellis wouldn't work in the ground as well as in a raised bed.
Before SFG method, most people staked tomatoes anyway.
Keski

the real issue of using sqarefoot on plot is soil fertility.
Since the soil mix suggested for use in a square foot garden is high in organic matter and designed for high density planting. Unless you plan on increasing your soil fertility to this level you will not get results simlar to a square foot garden.

Yes, you can do what you are asking. Just break the 20 by 20 into manageable chunks. My SFG area is 24 by 21 feet outlined in landscape pavers. You could follow same concept as this, but just do it in the ground. The key to SFG is building areas so you don't walk on your planting areas and you can get to any area of a bed for easy weeding. All your doing is breaking into manageable beds with walkways between each for weeding. You don't have to have Mel's mix, just amend your soil in the ground as best you can.

http://georgiahomegarden.blogspot.com/2011/04/2011-garden-square-foot-gardening.html

Here is a link that might be useful: My Gardening Blog

I used to do the square foot method 100%...the raised beds, the spacing, the dividing raised beds with string into 1x1 squares. It was very organized and pretty, but I soon realized that my climate does not do well with raised beds. Here in Florida, the soil is very sandy and drains quickly without the extra help of a raised bed. In my case, my plants would dry out every 12 hours unless we got a good soaking rain. I lost a lot of plants just because I didn't have time to water. I could've set up an irrigation sytem, but using more than my fair share of precious water did not appeal to me. I now garden using a lot of the SFG space-saving techniques such as spacing and trellising, but I am back on the ground. My plants seem a lot less prone to drying out and I get a pretty good yield if I stay on top of the fertility issues (nutrients seem to drain out of the sandy soil here as fast as water!). So, that's my experience. I've considered traditional row gardening, but I just can't come to terms with giving up any space to paths! Good luck to you!