GH raised beds - soil test results

pecker88 · April 11, 2017

March 2016 constructed greenhouse (heated, poly plastic covering) then built 30 ft x 5 ft raised beds on each side with a 5 ft walkway.

Heavy clay native soil. I filed each raised bed with ~1/2 compost (the City gives it away for free) and 1/2 sandy loam top soil from Northeast Nebr.

After a disappointing harvest last yr due to a variety of factors (new to GH growing, possible herb. contamination in compost, ect...) I decided to test soil last week. Results provided below.

I calculated total raised bed area to be 30 ft x 10 ft = 300 sq ft = 0.00688705 acres. Nutrient guideline says to apply 55 lbs / acre of Nitrogen.
To scale that down, I assume it's 55 * 0.00688705 = 0.38 lbs for entire GH ?

Same for Gypsum, recommendation is 355 lbs / acre.
355 * 0.00688705 = 2.44 lbs for entire GH

thanks!

PureHarvest · April 15, 2017

Yep.
TAke your .38 N and divide by your N source to get final weight of product needed.
Example: you have 5-10-10 fertilizer on hand. .38/.05= 7.6 lbs of 5-10-10 fert needed for the season to supply the N needed by the crop. You have to then decide what percentage you will apply at plant out and when you will apply the remaining portion.
I'd apply half the needs at pre-plant. And supply the remaining needs on weekly basis through drip feed.
You could also use Calcium nitrate and maybe skip the gypsum. I'd have to run the numbers.

brownrexx · April 15, 2017

I don't see why you would recommend adding 5-10-10 when the Phosphorus and Potassium are already high and in the problem zone according to the soil test report.

Why would you want to add MORE Phosphorus and Potassium?

I would add nothing except possibly a nitrogen source like blood or feather meal. I think that non organic gardeners use Urea for nitrogen .

I myself would not even add gypsum as your calcium level is close to adequate and there is probably a good bit still in the organic matter that is not broken down yet. You have a nice high level of organic matter. It is a new garden soil and has not equalized yet.

pecker88 · April 15, 2017

Quote:

Originally Posted by PureHarvest

Yep.
TAke your .38 N and divide by your N source to get final weight of product needed.
Example: you have 5-10-10 fertilizer on hand. .38/.05= 7.6 lbs of 5-10-10 fert needed for the season to supply the N needed by the crop. You have to then decide what percentage you will apply at plant out and when you will apply the remaining portion.
I'd apply half the needs at pre-plant. And supply the remaining needs on weekly basis through drip feed.
You could also use Calcium nitrate and maybe skip the gypsum. I'd have to run the numbers.

I always wondered how the NPK of a fert. gets factored in. Thanks!!

PureHarvest · April 17, 2017

5-10-10 was just a random example for calculating N.

April 15, 2017	#2
PureHarvest Tomatovillian™ Join Date: Mar 2014 Location: Mid-Atlantic right on the line of Zone 7a and 7b Posts: 1,369	Yep. TAke your .38 N and divide by your N source to get final weight of product needed. Example: you have 5-10-10 fertilizer on hand. .38/.05= 7.6 lbs of 5-10-10 fert needed for the season to supply the N needed by the crop. You have to then decide what percentage you will apply at plant out and when you will apply the remaining portion. I'd apply half the needs at pre-plant. And supply the remaining needs on weekly basis through drip feed. You could also use Calcium nitrate and maybe skip the gypsum. I'd have to run the numbers. Last edited by PureHarvest; April 15, 2017 at 06:18 AM.

April 15, 2017	#3
brownrexx Tomatovillian™ Join Date: Feb 2016 Location: Southeastern PA Posts: 1,420	I don't see why you would recommend adding 5-10-10 when the Phosphorus and Potassium are already high and in the problem zone according to the soil test report. Why would you want to add MORE Phosphorus and Potassium? I would add nothing except possibly a nitrogen source like blood or feather meal. I think that non organic gardeners use Urea for nitrogen . I myself would not even add gypsum as your calcium level is close to adequate and there is probably a good bit still in the organic matter that is not broken down yet. You have a nice high level of organic matter. It is a new garden soil and has not equalized yet. Last edited by brownrexx; April 15, 2017 at 10:19 AM.

April 17, 2017	#5
PureHarvest Tomatovillian™ Join Date: Mar 2014 Location: Mid-Atlantic right on the line of Zone 7a and 7b Posts: 1,369	5-10-10 was just a random example for calculating N.