Q. I would like your advice on raising raspberries using the Mittleider Method. What size grow boxes should I use? Should I use any special potting mix or fertilizers?
A. Detailed instructions are available in Gardening By The Foot or other books, CD’s or software, available at www.growfood.com. A brief review of raspberry-specific procedures follows.
Growing can be in the soil or in Grow-Boxes, and the width box or bed is a matter of your preference – either 18″ or 4′, with lengths to fit your growing situation as well. We recommend planting 2 rows of canes in 18″ beds at 8′ intervals.
Prepare the beds as you would for other garden crops, using Pre-Plant Mix and Weekly Apply to the soil before planting. Feed with Weekly Feed 4 times for single-crop varieties and 6 or 7 times for everbearing varieties.
If you are using Grow-Boxes, you do not need to fill them with “potting mix”. This is just very expensively packaged peat moss, vermiculite, and perlite, with $.25 of fertilizer in it. If you can find sawdust inexpensively, that is one of the best things to use in many places. In tropical climates, coffee hulls or coconut husks are often available and are also good. Bales of peat moss and bags of perlite are good to use throughout the USA.
Mix any combination of the above materials with sand in a ratio of about 30-35% sand by volume and 65-70% of equal amounts of the others. Cut your canes to the ground in the late fall and apply Pre-Plant and Weekly Feed to the soil, mixing it in as you hoe the weeds and remove any unwanted sucker canes.
Dr. Mittleider has grown raspberries very successfully in the same spot for 25 years by following these procedures.