It is appropriate to plant a field with what will earn you the most money or pleasure, or with what will best provide for the needs of your household. Raspberries accomplish all three of these goals and, with minimal care, are ready for the rigors of Colorado.
Drs. J. Reich, H. Hughes and J.E. Ells of Colorado State University (http://www.ext.colostate.edu/pubs/garden/07001.html) report that on average a 25 foot hedge of raspberries should yield between 15 and 25 pounds of fruit. This is consistent with my experience, but I will share some tricks to push the average yield to and above 25 pounds. With a market price often exceeding $10 per pound, an 1/16 acre of raspberries will produce something between $2,020 to $3,380 on about 338 row feet. When it is understood that it is easy to interplant trees (yielding something near to twice in value) among the raspberries, a 1/16 acre can provide perhaps even $12,000 of income to a family per year without greenhouse production. That’s $54,080 per acre, about $1.24 per foot.
Some farmers will trellis their hedges, holding them up with strings. Colorado State University recommends this method, but I do not. They recommend it because it prevents them from drooping and allows better weed control and harvesting. However, the natural tendency of the canes to droop is a reaction against environmental pressures, and helps them react to rain, snow, wind and hot sun – the rain penetrates to their roots better when they droop, the snow melts off or falls off without causing damage, wind is shielded from the center of a hedge when they droop and the canes catch less force. The sun is shaded better.
But you can help the plants better still by planting trees and making fences.
Plant your rows east/west so that they may receive better exposure to the south sun – the north wind does not trouble the dormant canes in the winter. Make sure to leave an equal amount of space for rows as for aisles: remember, plants have more below the ground than above, and if you squeeze too many too close together, you will reduce your yields.
It is good to till in the aisles regularly: tilling increases air in the aisles, improving microbial mineralization of the air, making the soil more fertile. It trims the roots and encourages the plants to send out rootlets – which are more efficient at eating this fertilization. It loosens the soil for the rootlets to eat easier.
If you have a ready supply of manure, you should put it both into the aisles where it will be tilled under into the root zone, and, in the spring at the first emergence of the leaves, upon the beds themselves. Raspberries love organic matter! Green manures are always best, and if your neighbor cuts his hay often (er, grass lawn?), see if you can buy his clippings for a small price. You could also invest in the production of green manure, but on small farms, this is not an efficient use of space. In the autumn in any case, plant oats, rye or other quick growing winter grasses in the aisles to till under in the spring.
Another good manure is that which is produced by animals. Bird manure is best for berries and does not require aging. But manure from four footed animals is not bad if it is aged and fermented with a bit of straw or other organic matter. Sterilized aged human urine mixed with wood ash is the most superior fertilizer after green manure. Composted human fecal matter is also superior to animal manure, but is difficult to produce safely and may be illegal in your area. Dog manure is similar to human manure (most people feed their dogs what they eat anyway – a corn, rice and soy based diet) and works in a pinch.
Manure should not be applied more than once every two weeks, and once per month is usually sufficient. When you have quantities of manure, apply once every three weeks except in winter, when your normal application rate ought to be halved – either half as much at the same frequency, or the same amount at half the frequency. The microbes are less active in the winter and there is only so much manure they can eat (plants don’t eat manure).
When establishing berries, make use of cloches until the warm weather of spring has come. The canes should be buried deep in the ground in Colorado, until only two or three nodes are above the ground.
Make sure to select several varieties. Let the bees hybridize your crop! Plant the canes far apart – 6 to eight feet in the row – and let the hybrids and roots of the berries fill in the gaps. You’ll have a healthier crop! Select your favorite berries from those produced and plant them to help your hedge grow stronger and better.
Trees should be planted to break the wind and provide necessary shade in the hot summer. Plant them close so that their leaves touch. While this may attract birds, you may always cover your berries (and trees) with bird netting to protect the berries. Let the birds eat the insects and protect your crop! Plant not only fruit and nut trees among your raspberries, but also habitat trees so the birds might nest above your fields.
Trees also provide mulch for the field in the autumn, and will apply it for you: their dropped leaves keep your field warm and active all winter long. The dormant canes keep the leaves and the manure you apply from blowing away. Trees are your best helpers.
Train grapes to grow up your trees for a bonus harvest, and you won’t be disappointed. Plant tulips or spring bulbs like crocus among your raspberries and you will have a valuable crop of flowers in the spring. It is not a good idea to intercrop annuals – raspberries are spiny and you want to leave the canes undisturbed.
Do not cut back your canes in the autumn. Thin them out in the spring. Do not till your aisles in the winter, wait to the spring. This provides better habitat for insects and small creatures your garden depends upon for the biodiversity that secures your crop.
Some canes will produce two years and then fail, others will produce only one year and fail, others do not produce the first year, but do on the second, and then fail. Some canes will produce even more than two years! The plant is not dead – it will send out new canes. Thin out in the spring at the first budding the failed canes so the plant will send out new canes this year.