Succulent Fertilizer Formulas

[Allen Repashy]

Hey everyone,

I am going to install a Fertigation system so that I can feed and water at the same time without much hassle. I am just digging into fertilizer formulas and am wondering if anyone has a recipe they would like to share for primarily Agave and Aloe production with an emphasis on stimulation growing out seedlings.

20-20-20...... 5-10-20?... 12-18-24? understanding the proper NPK ratio is still greek to me, as well as the different sources used for the nutrients... micronutrients? How about ppm for a constant feed system...

Anyone?

Allen

[agavegreg]

I tend to use a lower N and higher P and K. Too much N can lead to soft growth that is more susceptible to disease. Don't forget micronutrients, they are very important for good plant growth. The ppm will vary with the frequency of fertilizing.

Greg

[Allen Repashy]

Hello Greg,

Thanks for the input. I am trying to make it easy and feed on a continuous basis through the watering system other than during a few months of winter when it is cold and there isn't active growth. probably December-February for my climate here..... which is when we get most of our rains anyway...

My preliminary research is coming up with a range of 100-200ppm for this kind of regiment.

Allen

[Tim Harvey]

Optimal fertilization schemes will vary with the time of year also. I use higher N in the spring and early summer moving to more K in the fall, particularly for plants that are producing a lot of seed.

T

[Matt Maggio]

Is that 100-200ppm range expressed in terms of nitrogen? I would rarely exceed 200ppm N for aloes and agaves even during what's called pulse feeding For constant feed, closer to 150 sounds reasonable. I agree with everyone on the low nitrogen. The only time I may use a balanced N-P-K ratio is for pumping-up seedlings, or like Tim said, early in the season. For finishing and flowering, I recommend that the potassium (K) be at least twice as high as the nitrogen. Phosphorus should be disproportionately high as well. I've found that too much N can exacerbate potassium deficiency. High calcium is important for limestone species.
Your rate and frequency will depend on whether you use soil or soil-less growing media. Lower rate constant feed is geared more towards soil-less media. Also, have your water tested or obtain a water quality report to view nutrients already present in the water.

Matt

[Allen Repashy]

Hi Matt,

I browsed the Grow More selection and found a couple of formulas that seem to fit the discussion.

http://www.growmore.com/formulas/122626.pdf

And I found an interesting formula of theirs on another site:

http://www.ezfloinjection.com/pdfs/MSDS102030GM.pdf

The majority of the Nitrogen is in the Nitrate form..

Dylan Hannon was using a Grow More Hydroponic formula for growing bulbs and other types of 5-11-26 but I can't find the breakdown on this one.

I think this is the same product....... http://www.hydro-gardens.com/51126.htm

What do you guys think of these?

[Tim Harvey]

In this discussion, the big issue with any fertilizer is whether one can make a concentrated enough solution to use with an injector.

They say use 2-4 lbs/100 gallons. For an injector diluting 1:50 you would need to dissolve 1-2 lbs in a gallon for use as a stock solution. That can be the tricky bit. It might be that soluble, I don't know since I've never used it.

T

[Allen Repashy]

It says it is soluble "up to 4 pounds per gallon"... meaning on a really hot day

But according the the 10-20-30 spec sheet I linked to, they say that to have 100 ppm N, you only need 11 ounces for a 1:100 Injector ratio.

Not sure on the hydro formula, I haven't figured out how to do the math myself!

[Matt Maggio]

Ok.

Since we're getting technical, here's a sample calculation working with Grow More 10-20-30, where the ultimate goal is figuring out how much fertilizer to add to your stock solution(prior to injection) to achieve a desired PPM nitrogen in the FINISH solution, given a certain proportioner rate - existing tapwater N aside. Yes, I know Dosatron has an online calculator, but who cares

Say you want 100 PPM nitrogen in your FINISHED solution for a constant feed program, and the proportioner is set to a 1:50 ratio.

First, use that desired PPM N to find the amount of N present in 100 gallons of finish solution. Let's express everything in ounces by weight.

1 gal = 8.34lbs, So 8.34 x 16oz./lb = 133.44oz./gal, x 100gals. = 13,344oz.

100 gallons weighs 13,344oz. so use the following proportion:

If: 100oz. N
1,000,000oz. H20

Then: x oz. N
13,344oz. H20

1,000,000x = 1,334,400

x = 1.334oz. N in 100gals. at 100PPM nitrogen

That's just nitrogen. We need to know how much fertilizer is in 100 gal, So:

Since 10-20-30 has 10%N, divide 1.334oz by 0.10 to get 13.34 oz. fertilizer in 100 gal

To get the amount of fert. for preparation of the stock solution, bear in mind that a 1:50 ratio means that 1 gal stock solution gets proportioned for every 50 gal water, producing 51 gal finished solution.

If: 13.34oz. fert
100 gals. finished

Then: x oz. fert
51 gal finished

x = 6.80 oz. fert. in 51 gal finished solution

So, if 1 gal stock solution gets removed from the tank to make 51 gal finished solution, then you must dilute 6.80oz. of fert. for every gallon of stock solution.

Summary: 6.80oz. of 10-20-30/ gallon stock solution will produce a 100 PPM nitrogen finished solution, when proportioned at 1:50.

Make sense?

I looked at those formulas above. The NPK looks pretty good but notice there's no calcium or magnesium in the Grow More stuff. That's probably for incompatibility reasons with respects to phosphate. You may have close to enough Ca in the tap already for most crops, I'm not too sure for Mg You may have to supply these separately in space and/or time in conjunction with phosphate fertilizers or phosphoric acid - I'm tying threads into knots.

Here's a useful link for fertiigation IBT - Three Reasons to Broaden Your Fertigation Knowledge

Here's another good brand of fertilizer. Check out their CalMag Special for possible supplemental use.http://www.plantmarvel.com



Matt

[Tim Harvey]

Actually, it's my understanding that 1:50 dilution by convention means 1 part in 50, not 1 added to 50.

T

[Matt Maggio]

You've got me curious Tim. I learned on one of those brass siphons, 1:16 being most common. I was told that this is a concentrate to water ratio, and that the extra gallon must be factored in. I know brass siphons aren't in the same category as other injectors, but why would they be rated in the same fashion? If that's true, then substitute 50 for 51 to get about 6.8 oz for the above problem.

Matt

[Tim Harvey]

It is confusing. 1:16 really means 1 arbitrary volume made up to 16 x that volume by the addition of 15 volume equivalents of some other material. Using that terminology can get ambiguous though, since a 50% dilution is 1:1 ...

T