Shade and Sun Greenhouses

Anyone who grows seriously in western Washington state needs a greenhouse. It is far too cool and wet not to have one unless you are growing hearty natives. But since I like to grow non-natives and extend my growing season considerably, I need them.

The greenhouse of my choice is the Kensington brand from Costco. I have 4 each of the 6’ x 12’ and one 6’ x 8’. They have front and back doors, a very neat thermal heat expansion sun roof that opens and closes automatically and a vent in the front.

A shade greenhouse is good for plants that like warmth but not too much sun or wind. These are usually for people in warmer climates.

Both versions of greenhouses can add protection from bugs, unwanted cross pollination, severe weather (not all of course but generally) and a nice comfortable haven while you’re busily planting seeds and working with your plants until they are big and strong enough to withstand the natural environment.

For almost year round produce, I start planting in late winter (February) and end in late fall or early winter. Cool loving plants such as lettuces, broccoli, and spinach do quite well.

For those who insist on going green and organic, here is the Washington State Greenhouse Guideline from their website:

http://agr.wa.gov/FoodAnimal/Organic/docs/3002_ghguidelines_factsht_5_09.pdf

Greenhouse Guidelines
WSDA Organic Food Program has developed guidelines to help producers better
understand organic standards as they relate to greenhouse production. The
following points address common concerns regarding the production of organic
crops in a greenhouse setting.

SITES
Greenhouses must be located on a certified organic site or certified as a
separate organic site.

• Production of crops in soil within a greenhouse requires that the land in the
greenhouse has not had any prohibited materials applied for 36 months prior
to harvest.

• Production on benches and in containers does not require the 36-month
transition. For bench and container systems there needs to be
documentation that the greenhouse sidewalls and ceiling/overhead has been
cleaned with approved cleaners and is free of residual pesticides that would
contaminate the organic crops.

TRANSPLANTS
Transplants must be grown with organic practices as described in the Organic
System Plan.

• Annual Transplants – Annual transplants must be grown from organic seeds
unless organic seeds are commercially unavailable. Organic greenhouse
operations must have documentation from at least 3 organic seed supply
companies that organic seeds are not commercially available. In addition,
purchased transplants intended to produce an organic crop must be from a
certified organic source.

• Perennial Transplants – Perennial transplants must be produced from
organic planting stock or organic seed. If organic planting stock or organic
seed is not commercially available then nonorganic seeds/planting stock
may be used. Perennial planting stock must be under organic management
for not less than one year prior to selling the planting stock as organic
perennial transplants.

MATERIALS
Materials for use in organic production must be from non-synthetic sources or be listed on the National
List (205.601)

• Potting Medium – Just because the bag says it is organic does not necessarily mean it is. Make
sure the potting soil is approved through the current WSDA Brand Name Materials List or the OMRI
Product List. Potting soil mix may contain non-disclosed ingredients including synthetic fertilizers
and wetting agents.

• Rooting Hormones – Synthetic rooting hormones are prohibited in organic production. A strike,
scion wood or cutting treated with a synthetic rooting hormone must be under organic
management for one year prior to being sold as organic.

USE OF MANURE
Non-composted manure must not be applied within 90 days of harvest for crops where the edible
portion does not contact the ground or 120 days for crops where the edible portion does contact the
ground. [NOS 205.203 (c)(1)].

TREATED WOOD
Greenhouses may be constructed with treated wood provided that the treated wood does not have
contact with any portion of an organic crop, roots or contact the soil in the area of production.