I seems if you look around there are all kinds of small areas that you could put in a 3 by 4 garden of maybe just beans or anything! Look around it doesn't take much space.
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I always cover a weedy area with a small quick garden type raised bed. I simply cut the weeds then over with news paper and straw about 4 inches of straw! I then make a border of brick on top of the straw leaving the straw past the brick about 6 inches! I also put dirt over the straw on the outside of the brick just for looks and ocassionally throw a few flowers in the outside border like marigolds! II put a garden mix or some composted dirt to the height of the brick put in my seeds on top of the ground then add a 2 inch layer of potting soil or strained garden soil slightly over the height of the brick. In a few days the soil will settle and be at brick level!!. You can even add leaves to the straw!.
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Now you have made a new raised bed you can use for years! Because the area is small you can plant a little closer! This method will also make a great carrot bed! Putting the dirt around the outside of the brick keeps the border intact! Try it and you will have fun looking for areas that are wasted spaces in the sun or even shade! renmember the new raised bed is what you make it with the soil you use so try to use something with little weeds in it! A bale of straw will make many bed 4 by 4.