From

Location

Message

Date Posted

Eastern Pennsylvania

I would like to raise my Ca+ from ~1100 to ~2000, without impacting the pH level. I understand Gypsum is the way to go? How much Gypsum per 1000 sq feet? Also, is gypsum going to flood my soil with salt in the future? Thanks,
Jim

3/14/2006 3:23:37 PM

Eastern Pennsylvania

right...umm.. that's Safely :) as in not over-doing it.

3/14/2006 3:25:53 PM

SF Bay Area, California

As long as your PH around 7 or higher gypsum is the way to go, it will not modify your ph. If your PH is lower than 6.5 consider liming instead. It may take several applications to modify your calcium level to your desired levels. You can start initially with 10 pounds per 100 square feet applied evenly and tilled in prior to planting. Mid-season you can apply it again at a lower rate (5lbs per 100sq. ft.) by broadcasting it, raking it into the topsoil and then watering it in.

The best time to apply it is in the fall. This fall do a soil test first and then hit it again at 5 lbs per 100 sq feet if it is still called for. Keep in mind that gypsum adds calcium and sulfer but also help mobilize Mag. and Potasium and some other elements making them more likely to leach out of the soil. You may need to adjust these components of your soil if they are reduced too much by the addition of gypsum.

3/14/2006 4:46:07 PM

Eastern Pennsylvania

thanks. I guess I should clarify that my Ca+ is currently at 1100 and I would like to take it to 2000 (raise 900 ppm)since the Potassium is ranging between 500-750 ppm currently.

Can I get it at a garden center?

3/14/2006 4:55:48 PM

Omaha, NE (N41-15-42 )

Lowe's and Home Depot both carry it here in Omaha.

3/14/2006 5:46:45 PM

Paradise Mountain, New York

Your potassium is really high like mine. I've checked every where and found the answers to lower potassium.If you plant alfalfa in part of the patch this year and harvest the hay off of it,it will lower the Potassium level.But you have to throw the hay away and not use it in the compost pile. If you add it to the compost pile, your just putting the potassium back into the soil. Alfalfa removes more potassium then any crop out there. If you want to check this out yourself, do a web search on "Crop Removal Nutrients"

3/14/2006 6:09:37 PM

That State Up North

I added 1000 lb one year, and then 2000 lb of gypsum the next year to a patch that was 110x140 area. It worked well, and was not overdoing it. My pH was around 7.0-7.1 and I was also a touch low on S, so I added some of that, and all and all it balanced out well, I had more bigger fruit with better % heavy they year following.

Nic Welty

3/14/2006 7:16:37 PM

Simi valley, ca

I aint no expert but patch was at 2000 ppm then added 500 lbs for `1800 sq ft next yrs test said 1950 ppm so this yr iv added 600-700 lbs to 1800 sq ft ,, well we will see !!! O ya gypsum from home depot 4.00$ per 40 lbs ,. ps my potassium & mag has improved but iv added some,.

3/14/2006 11:39:58 PM

Mocksville, NC

Gypsum will do the opposite on your salts, gypsum will leach out salts, put it on now if ya can. Wet in if it doesnt rain before now, and planting.
Rog

3/15/2006 3:47:28 PM

Eastern Pennsylvania

Okay then, this weekend it goes on. I think 500lb is my absolute max. Gotta play it safe this year; I can always add more. Firing up the heater in the green house this weekend too and rolling out the veggies.
Jim

3/15/2006 3:53:35 PM

Garden State Pumpkins

I'd be a little worried about Ca/Mg ratio then the Ph...sever imbalances will tie up other nutrients...add everything thinking about all the balances you want to achieve..one by itself could be more problems that have to be resolved...GrowEmBig! Chuck

3/15/2006 6:42:07 PM

Eastern Pennsylvania

What is the correct Ca/Mg/K ratio? This is where I'm at now:

http://www.bigpumpkins.com/Diary/DiaryViewOne.asp?eid=45607

3/16/2006 11:17:01 AM

Ctpumpkin@optonline.net

I don't really believe in Albrecht's cation ratio theory. But since many folks do:

Cal:Mag~range~4-7:1 with the balance K. No Hydrogen.

3/16/2006 7:22:38 PM

Fredericksburg, Virginia

Jim,
Is ~2000 ppm optimum for growing big ones?

My soil test (Virginia red clay) this month read 1471 lb/A for ca with a pH of 5.6.

My Dad is a master gardner and said that to raise the pH 0.5 that I needed to add 100 pounds of lime per 1000 square feet. For sandy soil it was more like 25 pounds per 1000 sq ft.

Tom

3/16/2006 7:33:21 PM

Midwest

I attended a seminar on soil fertility and the advise was to maintain a Ca:Mg ration of 3-7:1 like Tremor posted and Mg:K of 1:1. I don't know if it matters but they advised not to till in gypsum. When on the surface, it will work itself down the soil strata. You haven't mentioned your OM%. If you have a high OM% (> 10%) and clay (not sandy) soil, your P,K should not leach out because the OM and clay will hold onto cations.

Tom: ratios are important. I think you can approximate how much Ca:Mg, K, P and Sulphur you may need in your patch. At certain ratios, it's easier for roots to exchange ions with the soil slurry. At optimum ratios, cations don't get tied up by clay and microbes and other soil organisms produce more soluable nutrients. If you have these things working correctly, the soil becomes ideal for mycorrhazae to grow, worms to thrive and roots will grow to maximum growth potential for the plant.

3/20/2006 11:23:45 PM