How many cups of fertilizer to add to 7 gallon plant?

[senormatt]

I've read just about all of the fertilizer threads, but I don't understand how much actual fertilize I'm suppose to sprinkle on my clumping bamboo. For example, about how many cups should I put on a 7 gallon plant that's in the ground?

[Alan_L]

It depends on the type of fertilizer, the strength of it, and some other factors. What type are you using, and what are the N-P-K numbers (10-2-8 or whatever)?

[senormatt]

It depends on the type of fertilizer, the strength of it, and some other factors. What type are you using, and what are the N-P-K numbers (10-2-8 or whatever)?

Thanks for the help! I have 3 different fertilizers on hand.


These two are Vigoro brand which I use for my st. augustine grass:

15-5-10

29-0-4

And I have this organic fertilizer ( http://www.ladybugbrand.com/products/8- ... ilizer.asp )

8-2-4

[senormatt]

Is there a guideline anywhere as far as how much physically to sprinkle on a plant? I've searched and read everywhere and haven't found anything. Everyone follows the 'just sprinkle until it looks like the right amount rule?'

[Mike McG]

Senormatt

Unless you have had a soil analysis performed and know exactly what your soil is lacking, if anything, I expect you would probably be mainly interested in adding nitrogen, the first number in the fertilizer analysis. As you noted, there is some flexibility in the application rate, but there are some simple calcs you can make to come up with volume type rate.

Assuming this is a recently planted bamboo, you should probably just spread the fertilizer in an area up to a couple of feet out from the center of the bamboo where the roots will start to spread. This is an area of about 12 sq ft. Later you can extend the distance. An area 3 ft out from the bamboo is about 28 sq ft and 4 feet is about 50 sq ft. A modest rate of nitrogen would be say a couple of lbs of N per 1,000 sq ft (about 88 lbs of N per acre). The first number on the fertilizer analysis is the wt% N,therefore for the 29-0-4, a 2 lb of N rate is about 7 lbs of that fertilizer per 1,000 sq ft. So for the 12 sq ft, the fertilizer rate will only be about 1.3 oz. For the same amount of N, the 15-5-10 fertilizer would require double this rate and the 8-2-4 approximately 4 times this rate.

If you know the bulk density of the fertilizer, you can use that to convert to volume otherwise I would just assume a “pint is a pound”, the same density as water. So 1.3 oz is only about 2.6 (say 3) tablespoons of fertilizer.

All that being said, I have alkaline soil as I expect you also may. When I do fertilize, which is rarely, I use an acidic ammonium sulfate type fertilizer that is made with municipal sludge (19-0-0) but also high in S and Fe. It is supposed to have slower release than plain ammonium sulfate (21-0-0). I usually mix it with twice as much pelletized sulfur and sometimes add a slow release multi-purpose fertilizer (don’t remember the analysis). On my clumping bamboo that has been growing for several years in the ground, I usually spread a “cup” of the fertilizer mix around about 3-4 feet out from the bamboo. The “cup” I use is an old plastic coffee mug and probably equal to two cups of measure. At that rate I am probably wasting fertilizer but the grass around the bamboo sure is green when it rains.

Mike McG near Brenham TX

[senormatt]

Thank you so much for the thorough response - it gives me some good direction. I'm curious if others use around 2 cups of fertilizer on their adult clumping bamboo - would love to hear more responses

[Mackel in DFW]

I never worry about over fertilization because I don't use synthetic fertilizers/ and use animal based organic fertilizers such as fish meal and blood meal only sparingly- if I thought high nitrogen was better for bamboo, I'd use it but intuition tells me high soluble nitrogen is not good for bamboo unless you're willing to water it a whole lot more. This brings in other problems such as leaching of micronutrients and salt build up due to municipal water. This year, the soluble nitrogen in my organic fertilizer program was only one percent. Insoluble about five percent.

Drought tolerance, something very important to me here in North Central Texas, has a lot to do with the type of microorganisms in the soil, and high nitrogen fertilizers are documented to destroy the fungal connections to the roots which extend the effective mass of the roots exponentially. I water deeply and use much less water than my neighbors and I am not an environmental whacko, more like a contrarian. I have no idea why some people espouse the use of high nitrogen on bamboo since bamboo evolved without fertilizing them just fine to reach seventy feet tall.

If anyone would like to tell me why high nitrogen is good for bamboo, go for it but I am a very doubting Thomas on this subject. The neighbors with beautiful yards who use synthetic or high nitrogen fertilizers literally water the crap out of their grass for a lush lawn. Bamboo is a grass is there not a parallel here....I use less water in my lawn less nitrogen and have an identical lawn with less weeds to boot and use no poisons....

My next door neighbor god bless him, waters his lawn three to four times more than I do, and our lawns are identical except he is always frustrated by the weeds popping up every season in his yard, he uses weed killer which I don't. I mind my own business, he hasn't figured out he is actually feeding those gloriouis weeds of his with all that nitrogen and shallow watering while I am feeding the soil and choking out the weeds naturally with a healthier approach in growing grass the natural way, low nitrogen ferts with a focus on micronutrients, infrequent yet deep watering.... I am really not an organic nut but I must conclude that my approach is cheaper, healthier and more fun....

The schmu bamboo guy who doesn't post here anymore used to espouse the use of heavy synthetic fertilizers all the time but his answer to why this is good was because he went to school to learn this stuff...that doesn't help explain the idea is anyone here wiling to back up why heavy soluble nitrogen fertilization is good for bamboo? Maybe different soils respond differently, that's the only hypothetical explanation I could come up with....

[Mackel in DFW]

Btw,

I am not trying to debate on the environment, who is more virtuous, who is smarter (I am a construction worker with a biology degree) etc, only, am interested in the science of the topic. High N or low N, what creates a better bamboo?

Regards,
Mackel in DFW

[Samajax]

Interesting topic and I certainly don't have the answer.

I've only really known one way of fertilizing..the organic style, so I have no comparison. I'm with Mackel in DFW- I feed the soil.

There are no organic products with high "N" numbers (19 into the 20's)- blood meal/corn gluten meal is about as high as you can go when using "organics". I think those are right at 10.

I'm no expert- and please correct my errors, but most plants need the fungi/bacteria in the soil to process any available nitrogen. Nitrogen is "locked up" unless it's processed by the soil relationships. It's a root zone friendship. With great soil activity, more nutrients are taken in by plants- be they trees or grasses. I might be wrong, that in trees it's more of a fungal relationship and in grasses, it's a bacterial one.

So what do I do to my lawn/bamboo? I compost once a year, put out dried molasses (sugar for the soil bacteria) and put out lowish amounts of organic style grass fertilizer 2x/year. When I apply it to the bamboo, I take my claw and work it into the top one inch of soil. I put out manure, sometimes. I've never worried about putting out too much because of the low NPK numbers, but it's not like I've ever dumped huge amounts.

I've never used Ironite (personal choice, it's an industrial waste by-product), but Green Light out of San Antonio has a great organic iron/acidifier if needed.

I've never had burn and the plants- depending on rain/winter temps, look great.

I'm sure we all develop a gardening style that works for us...that's my $.2 cents worth.