Good question, I'd ask them. My gut feel is that they do mean cups. Citrus Tone is good stuff, but I starved my trees when I was using it... I simply had a difficult time getting enough CT down around the small root area of the young trees.

I changed my feeding plan as a result. I now apply GroP along with other fertilizers. My goal is to grow the trees as big as possible, fruit production is NOT my priority right now. Therefore, I target 1 lb of N for the [4-6 year old ] trees annually, but need to double the application due to losses from irrigation, slope, poor soil, and heavy wood mulch. So the actual target is 2 lb. N.

To get to 2 lb of N and also supply other essentials, I generally give the trees 3 cups AS or NK per feeding early in the season and then 2 cups GroP AND 1 cup Ammonium sulphate (or other fertilizer on hand such as NitraKing) later in the season (like right now) when I do not want to encourage more foliar growth... and help the trees make fruit.

The general assumption is that 2 cups is a pound of fertilizer. To get 1 lb N using NitraKing (21-2-4) or AS (21-0-0) divide 2 cups by the percent N - - - -

2C / 0.21 = 9.5C therefore I need to apply 9.5 cups AS or NitraKing to get 1 lb N down... ( 2x gives me an actual target of 19 cups - per year if just applying AS or NK).

For GroP: 2C/.08 = 25 cups

Therefore I give the trees 2 cups GP and 1 cup AS per feeding and try to get 9 or 10 feedings in annually.

The math is easy, throwing the fertilizer down is relatively easy, getting the fertilizer to the target roots and having them take it up.... that is the challenge!

Good luck and let us know what you hear from GroP.! - George

Mole has a very good grip on this feed stuff. Me! I would use Espoma 5-2-6 and add ammonia sulfate at 1/4 strength (5.25-0-0 to give me 10.25-2-6 a perfect ratio. You can measure this out in weight.

If i am using gro power of 8-6-8 I would add grass feed 8-0-4 at 3x for 24-0-12 and end up with 32-6-20 and feed. I have Miracle Gro 24-8-16 and I add 2X of 8-0-4 grass feed to get 40-8-24 I don't always have access to the feed of the number I showed but I can get close. For citrus the nitrogen is the most important followed by a relatively low middle number.. Its not close to rocket science. Just get into the ball park and your trees will thrive. It is late and I will check this for accuracy tomorrow

6b Steve.

Thanks George, have an email in to Gro-Power and will update. With Citrus-Tone, I was fertilizing at the ~0.75 lb N / yr level. This worked out to 15 lbs (45 cups) spread across 3 feedings. If I only feed 2 cups (assume = 1 lb dry mix) of Gro-Power 3x per year as label recommends, the trees would receive "only" 0.24 lb N. Now, following your schedule of 9-10 applications instead of 3 (or tripling the size from 2 cups to 6 cups at each of 3 feedings), they'd get the .75 lb N. Hence my confusion.

Steve, since they're percentages, if you mix 1x 8-6-8 with 3x 8-0-4, don't you end up with a mix of 8-1.5-5? Similarly, if 1x MG 24-8-16 mixed with 2x 8-0-4, that's a mix of 13-3-8.

Either of those are a good ratio. you need to use enough of that mix to get the weight of each component the plant needs. I am not good with math but what I tried to show is you'll need to augment the one you have with the ratio of stuff I suggested to get the nitrogen up to snuff with out overloading either the P or the K.
6b Steve

Response from Gro-Power:

"It is always hard to determine application rates for trees, since there are so many shapes, sizes and ages. If it is a fairly young tree, I would probably stay with the 2 cups. If it is mature and has established roots into the soil, you probably can go heavier. 12 cups sounds like a lot, so I don't think I would go that heavy, though."