Soil

Modified UC Mix - Our own custom mix. It is the most commonly used soil at our facility. Download soil analysis (PDF)
Here are the ingredients:

1 part ground canadian sphagnum
1 part uniform coarse sand(No silt)
1 part white pumice
1 part redwood compost
3# oyster shell/yd
3# dolomite/yd
3# single super phosphate/yd

Yolo Fine Sandy Loam - Local field soil, devoid of organic material.

Sunshine Mix #1 - Commercial peat based media from Sun Gro Horticulture.

Fertilizer

Our fertilizer supply is based on a packaged pre-mixed material from GrowMore, Inc. Our systems are a "continuous feed type" also know as fertigation. This means fertilizer is always in the irrigation water. Plants receive a small amount of fertilizer at every irrigation. Fertilizer concentration can be adjusted per greenhouse or per bench if at the Core Greenhouse complex. We have two types of fertilizer systems depending on which source water used. The source water is either industrial tap water from local wells or reverse osmosis water created at the greenhouse facility. Fertilizer injection into the source water is performed by Dosatron injectors. The macronutrient ratio for Nitrogen:Phosphorus:Potassium is 2:1:2. No boron is added to the irrigation water. There is sufficient boron in the pottting soil, de-ionized water, and ample amounts in the industrial tap water.

We also have Hoagland's complete fertilizer concentrate in our headhouse for those special times when the irrigation water is not appropriate.

Fertigation systems description

Reverse osmosis - This is used in nearly all our greenhouses. GrowMore 4-18-38, calcium nitrate, and magnesium sulfate are injected into the water. pH is usually at 5 - 6, and electrolyte conductivity is low.

Industrial water - GrowMore 20-10-20 or GrowMore 10-15-20 are injected into the water. pH is greater than 7 and electrolyte conductivity is high. Some plants do not grow well on this water.