We're (my wife and I) doing SFG for the first time this year. We've been reading books and reading articles on the Internet, but we realize that there's nothing like first hand knowledge. So if anyone has any hints, tips suggestions, ideas, etc please send it to me. I appreciate everyone's time with this. I hope everyone is doing well.
Square foot gardening is a form of Intensive Gardening--so that may help you in your internet searches and reading. My suggestion is to start with a small garden and gain experience with this method. Use quick-maturing and dwarf varieties your first year and try to plan succession crops--to make the best use of your space. That means you will need to map out your season with estimates of days to maturity for each crop and which crops can follow and still come to harvest within your growing season. Small gardens lend themselves to using plastic tunnels to extend the season--so you might give that a try at the end of this season. It's important to know the footprint of each crop at maturity when you plant intensively. Look for a growing guide that includes the foot print (breadth) of each veggie at maturity -- such as the book Square Foot Gardening (he covers the top 20 or so veggies) or The Kitchen Garden Growers Guide (which covers 80 veggies). My experience has found that the Square Foot book footprints are on the conservative side--so I allow a bit more room.
You can combine square foot gardening with raised beds and/or with deep mulching techniques. I've found that if you combine square foot gardening with deep mulch techniques you're going to end up with a raised bed eventually, LOL!
You need to take into account the actual size of the plants when considering spacing. All pepper plants are not the same size and the 12" spacing may be plenty for some and not enough for other, larger varieties.
Mel actually says this himself, the spacings he "recommends" are really only rules of thumb. Check the suggested spacing on the seed packet, whatever it suggests between plants (not rows) is how far they need to be spaced apart in the square foot garden. So one variety of eggplant may say 12" spacing between plants and another, 18". Go by the specific recommendations for that variety. So an indeterminate tomato will need more space than a determinate, bush variety.
He also suggests growing "up" rather than horizontally. You can have even watermelon in the square foot garden by training the vines up netting or plant fence. You'll need to support the developing fruit but they'll be easy to see, it's not hard to do. Some people use old pantyhose as they stretch as the fruit grows. Just make a sling attached to the netting. A bamboo stake stuck in the ground at the to help support the netting wherever you have a watermelon supported can be used if necessary.
Of course you wouldn't want to try this with really large varieties of watermelon, but sugar babies and other ice box types are pretty simple to manage. They recommend only one fruit per vine with this method but I've never bothered to prune them back and it worked fine for me.
Something that I am trying this year is planting as many companions in the same spot as possible. For example, I have some hay bales growing beans and have started some corn in peat pots, so that I can drop them in between the bales so that those two sisters can grow together.
I've also pretty much done away with the concept of rows for anything. I have 4'X (something) sized beds that are two bales side by side by however many long, and I can very easily reach all the way to the middle, so I'm getting a LOT more in a space by not bothering with rows.
I've also planted my cabbage, cauliflower, brussel sprouts and broccoli in triangles, not rows. I've got 3 plants per bale (2' X 4' ) because of it, and they have decent space to grow in. In between the plants, I've also prepped it to lay down tapes of lettuce, so that I can enjoy the greens as the other plants grow.
The only thing that is driving me nuts are my tomato plants, but even they are starting to thrive. I have them next to the posts of the bed that has posts, and will be tying them to the posts. I read somewhere that potatoes and tomatoes can grow together, so there is a section that has potatoes next to the tomatoes, just to see what happens.
These are just my personal experiences, and I will be the first to admit that I am probably breaking half the rules out there. It's just that it's so much fun to try stuff though.