Organic Technology at High Altitude Rhubarb
We have pioneered a unique system for organic agriculture that obviates weeding and crop rotation while conserving water and minimizing the need for soil amendments beyond the initial preparations for planting. The technique has proven extremely successful since 2002. This page will explain the motivations and details of that technique and the results it has produced. We've used no chemical fertilizers since 2002. We've never used pesticides. We farm at 7750' near the easternmost foothills of the Rocky Mountains in a forested area known as Black Forest. It is a semi-arid forest which owes its existence and differentiation from the surrounding high plains grassland to the fact it straddles an east-west ridge almost 3000' higher than the plains to the north (Denver), and the south (Colorado Springs). The elevation results in additional precipitation sufficient to support the forest.
Goals, Constraints, and Resources
Published information on organic systems gave evidence that viable systems for any particular farm will probably incorporate resources or characteristics somewhat unique to that farm. For example, most of the published techniques are unusually labor intensive, thereby well suited to a large family or source of inexpensive free labor. Likewise, systems involved a variety of non-agricultural components, such as chickens and cows (aka ranching or animal husbandry), and therefore required expertise in those endeavors as well. So we started our quest for a suitable organic system by first identifying our constraints and resources with an emphasis on those unique to our situation and relevant to our goals.
Choice of Crop: Why rhubarb? This ideal crop revealed itself to us without much effort on our part. We have planted most typical U.S. food crops in our garden. Most proved unsuccessful due to the very cool nights, and short growing season, the frequent summer hail storms, the deer, or some combination thereof. Rhubarb, on the other hand, so enjoyed our situation we could almost hear it growing during the quiet nights!! Go figure. Anyway, we've been urged to add additional crops to increase the credibility to our endeavor. While we are searching for additional opportunities, and some are promising, I maintain that a successful organic system makes optimal use of the available resources and climate. The end result should be high, possibly the highest, quality products for crops suited to the area., and should leave the soil better than before farming. I considered an organic greenhouse but that appears to be an oxymoron and, regardless, requires too much water. As our civilization has expanded to occupy areas ill suited to traditional farm production (and that includes organic and inorganic) we need to accept the fact that our diets need to adjust to the possibilities of our environment as much as healthy nutrition will allow. Not every organic farm, organic breakthrough, or organic principle will apply equally to all situations. Now, for an outline of our own situation and system.
Our goals were few and simple: Generate enough money to pay our property taxes and utility bills so we could afford to retire here; Involve very little maintenance expense or labor (we're getting old); and be 100% organic. We also hoped it would be fun. The results have exceeded our goals.
Our constraints included: A small, part-time, aging labor force; a scarcity of water; shallow, highly varied and always poor soils rich in viable weed seeds; a dense extant population of prairie vegetation; the certainty of invasion by noxious weeds when the soil is disturbed; a semi-arid climate; an omnipresent potato blight which had ended all commercial potato production on nearby land a few decades ago (once a thriving local industry); a short growing season, zone 4; frequent summer hail storms, sometimes up to 8"; and hostile winters. Our winters are a formidable problem for most perennial crops such as fruit trees. Normal winters here include mostly cold, often snowy days sometimes dropping below zero for a week or two. However, they normally also include a week or two of 60o days in January. Most perennials wake up then, thinking it is spring, to promptly die in the subsequent freezing temperatures of the following weeks. As you might imagine, farming is uncommon here.
Noteworthy resources included: a large, inexpensive supply of tree mulch (We live in a partially forested area of Ponderosa Pines. The El Paso County waste management program accepts and grinds tree slash and then provides the resulting mulch, all for free. It reduces volume in the county dump.); A large knowledge base specific to our locale (Farming is now uncommon here but there is an active garden club and a number of helpful, long time residents.); 14 hours of intense, daily sunlight throughout the growing season, and; friendly, understanding neighbors.
We experimented with soil amendments and various crops and discovered that rhubarb is well to this situation. The main harvest precedes the hail season. The plants thrived in properly amended soil. The fungus and insect known to threaten rhubarb appear in short supply. Deer and other herbivores don't like it. Rhubarb demonstrated itself to be a rare perennial which easily survived our weird winter conditions. Also, there was unsatisfied local and regional demand for the product, both plants and the vegetable harvest. All that remained was to find a way to reduce the water requirements and find an organic method to address the risks.
The inexpensive mulch offered a solution to the problems of water scarcity, organic feeding, and weed control. (The mulch is free but we incur transportation costs transporting it to the farm.) After several years of experimentation we had found effective strategies for soil amendment and maintenance which addressed the remainder of our goals and constraints...low maintenance but high yield. Turns out we love working outdoors and producing food. Also, a pick-your-own sales strategy adds a considerable element of fun to the whole operation. More details of the system follow.
Our Current Organic System-The Details
Our operation began non-organically. However, our current organic approach produces sizable harvests, yielding about 45 pounds of stalks per plant for the premium victoria variety in the initial harvest. Hail permitting, we can harvest about half that for the second harvest. We harvest at most 50% of the biomass at each harvest, meaning the initial size of the plants includes 90 pounds of stalks. Initially establishing a bed or field requires considerable labor and cost. Subsequent maintenance labor and costs, however, are very little. Water requirements are lower than non-organic approaches and virtually no weeding is required. Pernicious for many crops, the odd bindweed is our most robust weed. It is impotent against rhubarb. We nevertheless pull any appearing in the mulch. The few weeds unfortunate enough to start in our only surface soil, centered directly under the rhubarb plants, live an anemic existence and seldom even find the sun. The exposed soil is at most 2 feet in diameter under the center of the plants. Our larger plants have leaves up to 30 inches in diameter and the plants reach 8 feet in diameter, 50 inches high--A hostile environment for any competitors.
During our non-organic startup we found that our soil required considerable amendment. It was overgrazed to the dirt by horses. The soil was high altitude prairie grassland, compacted and barren of all but weeds with some grasses and wildflowers struggling back. Our native soil is "Kettle-Pring-Peyton association: Deep sandy loam and loamy sand soils on arkosic sandstones."1 The top soil was only 1-2 inches thick and an unfriendly mix of clays and sand. The initial beds were prepared in 1995 in a non-organic manner. First, 3" of compost was tilled into the top 6" to 8" of soil and this 
was further amended with sufficient high nitrogen fertilizer for beds 10 times the size of our beds. The beds were then broadcast watered several times during the growing season. Weeds and grass germinated but were promptly killed by the high nitrogen concentration. The beds went fallow. The following year the soil we had the soil tested. The Colorado Extension Service reported they had "never seen such ideal, rich soil but it was rather high in organic material." For the next several years the soil and plantings, which included 12 rhubarb plants, were maintained in a non-organic manner...chemical fertilizers were used twice per year to 
produce harvests of a variety of crops suitable to our area, including beans, peas, squash, carrots, beets and garlic. We also experienced disappointing yields or complete failure of many crops not well suited to our particular location, including tomatoes, basil, pumpkins, potatoes and corn. We continue to experiment with different crops on a very small scale...in our home veggie garden. Organic growing began in earnest in 2002. A bed of 35 plants was started from the roots of two of the originalinal 12 plants. The unique aspect of our technique deals with soil preparation and composting. With our technique there is no need for spreading large amounts of compost, additional soil amendments or weeding.
Organic soil preparation went as follows. The soil was heavily amended with mature compost, tilled into the top 6"-8" of soil. Then the amended soil was piled into small buttes, each about 1.5' tall and 6' apart, center to center. (See photo below) Then a rhubarb root was planted in the center of each butte and a water ring was formed on the top. The outer perimeter of the bed was then covered with a 4' to 5' strip of landscaping fabric to form a barrier to surrounding plant roots and seeds. Then the fabric and the beds themselves, 
between the buttes, were covered with ponderosa pine mulch, reaching a thickness up to 2' between the buttes and about 6" on the perimeter fabric. The deep mulch, combined with the rhubarb leaves themselves, makes it virtually impossible for weeds to grow in the beds. Any that do are easily pulled by hand or ignored as they have negligible impact on the harvest. Earthworms were also added to the soil around each plant. They appear to remain in large numbers years later. The area surrounding the beds is kept mowed to prevent any seed production within 20-40 feet of the beds...and for aesthetics. The mulch composts in place and thereby provides the lion's share of plant nutrients. Some of the composted nutrients undoubtedly leach into the soil around the plants and the lowest levels of mulch compost to directly provide a home for future root growth. We avoid mixing uncomposted mulch in quantity with the soil. This would bind too much nitrogen in the bacteria decomposing the mulch. Nevertheless, soil and compost gradually erode and mix from the buttes to form a rich, deep layer of soil all around the plants. In our semi-arid climate the mulch must be topped off with another 3"-6" of mulch about every 5-6 years. (Semi-arid: 13" of rainfall-equivalent per year.) It would probably be more frequently in a wetter environment. The mulch 
not only continues as a weed barrier and constant source of fresh compost but it also helps with moisture retention in the soil, considerably decreasing the frequency and volume of water applications. In our semi-arid environment our supplemental watering has never exceeded 50 gallons per plant in one year...and we've had some very dry years. Normal years involve 3-4 waterings, 10 gallons per mature plant each time.
In the fall, right after the plants have gone dormant, we cover each plant with 1"-2" of mature manure compost and water this in. This helps the plants winter over and provides a nutrient boost in the spring. The primary function of the winter compost blanket is to provide material for water rings in the following year and to render the plants immune to the local phenomenon of 2 weeks of spring in the middle of winter.
As the first plants appear in the spring we pull the compost back to form a new water ring around the plant on the top of each butte. (See photo of new growth). This additional compost is small...about two shovels per young plant per year, 5-6 per mature plant. Nevertheless, it is sufficient to raise the top of the buttes to compensate for natural erosion. As the buttes rise and the surround mulch composts, the buttes begin to protrude above the mulch (see water rings 
photo). Therefore, after 5-6 years it is necessary to top off the mulch with another few inches of fresh mulch. This provides continued food for composting and ensures an uninterrupted and even cycle of plant nutrition and growth. Additionally, walking through the rhubarb fields is an aesthetically pleasing experience. They are not only pristine in appearance but the deep mulch creates a very cushioned walking experience and makes it easier to get on your knees.
Much of our moisture comes in the form of snow. Most snow sublimates, rendering it of little value to the plants. Nevertheless, as the plants have matured to maximum yield of 90 pounds each their annual water requirements have grown from 10 gallons 40-50 gallons. The 40-50 gallons is provided in 10 gallon increments. Smaller and younger plants are watered with the same frequency and with proportionately less water. The resultant plants are very healthy with the largest variety producing about 30 pounds of rhubarb per plant in the first harvest and growing to 90 pounds per plant when fully mature. However, each harvest is limited to 1/2 of the annual growth so as not to overstress the plants. We believe the harvest must be limited in that fashion in order to achieve the long intervals between replanting we have thus far witnessed. In fact, we have yet to replant after 8 years of growth and 5 years of harvests. Normally, rhubarb fields are replanted every 5 years or annually.
Maintenance: The net effect of all this is that the maintenance chores are: 1) water 3-5 times per year, 2) apply a compost blanket in the fall after removing any remaining debris from the year's growth, 3) pull the blanket back to form a water ring in the spring, and 4) about every five years top off the mulch with 3-6 inches of fresh mulch. Water requirements are between 0.5 to 1 gallon per pound of harvested product per year, varying mostly with the amount of natural precipitation during the growing season. Yet to be discovered is the longevity of these beds...we're at 8 years and counting as of 2010.
We will gladly answer any inquiries and assist anyone in adopting a similar approach to organic growing. We also invite you to share your own experiences with us to help us all better understand the issues of organic agriculture. Just contact us.
1: According to the U.S. Department of Agriculture, Soil Conservation Service