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Home  > Question of the Week

Question of the Week

Permalink What do I need to do to get manure certified for use on organic crops?


Answer: Animal manure, both organic and conventional, is approved for use on organic farms, subject to certain restrictions. The relevant sections of the National Organic Standards are listed below.

The standards state that manure may be applied to organic farmland, subject to certain restrictions.

Manure must be applied and incorporated at least 90 days before harvest, if the edible portions of the crop do not touch the soil, e.g. apples. The manure must be applied and incorporated at least 120 days before harvest, if the edible portions of the crop do touch the soil, e.g. carrots. These rules were meant to ensure that disease organisms will not contaminate human food. There are no restrictions on the application of manure to feed crops, such as alfalfa.

Manure that is composted according to an approved process (listed on the following page) can be applied to organic crops at any time. If you plan to compost the cattle manure, you may wish to list the compost on the Brand Name Material List with the Washington State Department of Agriculture Organic Food Program. This is a voluntary program. You can find more information at or call (360) 902-1805. The compost itself is not “certified organic,” it is approved for organic agriculture.


§ 205.203 Soil fertility and crop nutrient management practice standard

  1. (1) Raw animal manure, which must be composted unless it is:
    • (i) Applied to land used for a crop not intended for human consumption;
    • (ii) Incorporated into the soil not less than 120 days prior to the harvest of a product whose edible portion has direct contact with the soil surface or soil particles; or
    • (iii) Incorporated into the soil not less than 90 days prior to the harvest of a product whose edible portion does not have direct contact with the soil surface or soil particles.
  2. (2) Composted plant and animal materials produced though a process that:
    • (i) Established an initial C:N ratio of between 25:1 and 40:1; and
    • (ii) Maintained a temperature of between 131 and 170 degrees for three days using an in-vessel or static aerated pile system; or
    • (iii) Maintained a temperature of between 131 and 170 degrees for 15 days using a windrow composting system, during which period, the materials must be turned a minimum of five times.


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Permalink I have a question about hoop house strawberries, especially elevated beds with various substrates. Can someone help?


Answer: Your research request suggests that you are primarily interested in hydroponic strawberry production. Hydroponic means that a non-soil based medium is used as a substrate and fertilizer and pest control happens through the irrigation system. If this is the case in your situation, perlite is a common medium used for hydroponic strawberry production. Since the substrate is typically expensive as is the nutrients, the bed width is kept to a minimum and alternative containers are typically used.

A study published by the USDA-Agricultural Research Service describes a few different hydroponic strawberry production systems and suggests a few varieties that work well in a hydroponic system. One of the systems is a vertical system of which they have the following suggestion. “Light intensity greatly affects strawberry growth and development. Since light levels reaching the plants at the lower section of the towers were only 20 percent of levels measured at the top, fruit production was reduced. Slightly taller pots spaced farther apart on the towers would reduce this problem.” They also describe a system that is initially capital intensive, but has the potential to bring high returns.

This research report is available online at the following link:
Hydroponic Strawberries Avoid Soil Pests
By: Doris Stanley; November 1998; Agricultural Research magazine

Another study on hydroponic strawberry production showed that certain varieties yielded well under hydroponic conditions and were less susceptible to powdery mildew and aphid predation. In this study they did not use fungicides or pesticides and had yields that were almost 2x greater than field grown strawberries. They outline the advantages and disadvantages of greenhouse culture in this publication:

  • Soil fumigation in not required.
  • Yields per acre up to five times greater than field grown
  • Quality of fruit is increased
  • Grey mold and anthracnose are not a significant problem
  • Fruit can be produced and marketed as pesticide-free.
  • Harvest efficiency can be improved by 25-30%
  • Production is increased during the early season.


  • Start-up costs for greenhouse production can be high.
  • Grower knowledge deficit. Growers are skilled at highly intensive field
    production; they must adapt their skills for greenhouse production

The study, “Protected Culture of Strawberry as a Methyl Bromide Alternative: Cultivar Trial,” by: Ashwin V., et al. 2003 can be viewed online in the embedded link. [PDF/34K]

PVC strawberry production is a hydroponic system using large (4″ or greater) PVC pipes cut in half to make troughs to hold the substrate and plants in. Below I have listed a publication that describes the PVC Trough system among other systems complete with pictures and substrate information for a hydroponic situation. They also looked at different substrates to plant the strawberries in—peat mix, perlite, and pine bark. All of these substrates yielded virtually the same, which is not surprising, as all of the nutrients in a hydroponic situation are from the hydroponic solution (Paranjpe, A., et al. 2003).
Winter Strawberry Production in Greenhouses Using Soilless Substrates [PDF/285K]
By: Paranjpe, A., et al. 2003.

If hydroponic production is not your intention, below is a great overview by a horticulture specialist at Cornell University who specializes in greenhouse berry production.
Berried Treasures: Off-Season Production of Strawberries and Raspberries
By: Marvin Pritts - Department of Horticulture. Cornell University. 2000.

If you are particularly interested in organic strawberry production it is important to consider fertility management for organic strawberries. For sustained organic fertility throughout the season (which is what an everbearing will need,) a common practice is to apply enough high-N materials, such as fish meals, seed meals or alfalfa meal, to supply 30 pounds of actual N per acre. Compost can be used as a supplement and serves well to condition the soil and balance nutrients but does not provide enough available N at the time needed. An inch of compost and the appropriate amount of a high-N organic material spread directly over the rows is recommended (Sideman 2002). For information on organic hydroponic nutrient solutions see the further resources section below for Mary Peet’s power point on the topic.

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Permalink What information can you give me regarding organic melon production?

North Carolina

Answer: In general, melons prefer an average soil pH. of 6.0 to 7.0. It is critical that the ground be warm enough for the seeds to germinate! Plant melons 4 to 6 feet apart and sow the seeds 1 inch deep. To get the plants off to a good start, plastic mulch helps to keep the soil warm. They can either be direct seeded or transplanted, but transplanting insures you will have a stronger plant starting in the field.

Organic soil management:
Melons are heavy feeders. It is important to work plenty of compost into the soil before planting. Soil enrichment, rather than plant enrichment is a tenet of organic production. For more information on organic soil management I recommend the ATTRA publication, Sustainable Soil Management and Soil Management: National Organic Program Regulations.

General Management:
Melons need plenty of water during the growing season, so it is a good idea to use soaker hoses or a drip irrigation system. Floating row covers placed over the growing plants help deter insects and create a nice, warm micro-climate. Place the row covers on new transplants or a newly seeded bed immediately after planting and remove them once flowers appear on the vines. This is important for pollination purposes.

Organic Pest Management for Melons/Cantaloupe:
The major pests of watermelon cantaloupe are the same that afflict Cucurbit crops in general. A good guide for general organic pest management is titled, Resource Guide for Organic Insect and Disease Management. It is based in the Northeast, but should still be applicable to your situation. They have a specific section on Cucurbit pest management, which I find to be quite comprehensive. You can access this publication online at: or the chapter on Cucurbits at:

Cucumber beetle is a major pest of cucurbits in general. The ATTRA publication, Cucumber Beetle: Organic and Biorational IPM is a good resource for Cucumber Beetle control.

A number of viruses and diseases such as cucumber mosaic (CMV), squash mosaic (SqMV), and watermelon mosaic (WMV-1,2) as well as powdery mildew, downy mildew, and gummy stem blight. These diseases can be controlled by using disease-resistant varieties, having a good crop-rotation system, growing on soils with good air and water drainage and judicious use of organically approved materials such as copper compounds.

The New York Cooperative Extension vegetable page list different watermelon varieties that are resistant to the above diseases and viruses. You can access this information at the following link:

The Kaolin Clay based product, Surround WP has show to have significant control with many cucurbit crop insect and disease pests if sprayed 2-3 times per season. The ATTRA Cucumber Beetle publication mentioned above discusses this strategy.

The ATTRA web site has a useful database of biorational pesticides that will be helpful to refer to as your season progresses. You can search by pest or by product. The link to this database is:

Weed control can be achieved with plastic mulch, which also helps warm the soil in the early summer months. Otherwise, weeding in the initial part of the season is essential to prevent water competition. Once the plants spread out weeding becomes less critical.

Marketing and Enterprise Budgets:
It is important to determine the profitability of this crop before growing it on a significant scale at your farm. The most important way of determining this would be to do an enterprise budget for your region. I would encourage you to look at the North Carolina Market Ready site for a lot of enterprise budget templates for watermelon. Some substitutes for extra labor in weed and pest control would need to be accounted for. You can access this web site at the following link:

Watermelons have a good direct market and never seem to have a problem selling at farmers markets. The Rodale Institute Organic Price Report has weekly wholesale fruit and vegetable prices. I did confirm that they have cantaloupe prices under the "Fruit" category. The direct link to the New Farm OPR is at:

T.H ~ NCAT Agricultural Specialist

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Permalink What type of Sunflowers can be used for dried edible seeds?


Answer: A quick search on the Cornell Ornithology website revealed that black-oil sunflower seeds are most preferred by birds. While you can also include the larger, striped sunflower varieties, the smaller, oilseed varieties are enjoyed by a broader species of birds.

The National Sunflower Association also has an extensive section on their website on sunflower variety selection for bird seed at:

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