StellerKeller
Active Member
There's the question. Is 10-10-10 more concentrated than 7-7-7? Anybody ever use African violet fertilizer?
Q: What is the diff between 10-10-10 and 7-7-7?
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racerboy71
bud bootlegger
- eHow
- Home & Garden
- Plants, Flowers & Herbs
- Flower Basics
- What Is the Difference Between 12-12-12 Fertilizer & 13-13-13?
By Marie Roper, eHow Contributor
Choosing the right fertilizer is important.
Walk into any garden center and you're met with shelves of fertilizers, all promising you beautiful, lush gardens. The choice can be overwhelming. The most important information on any fertilizer package, however, is the N-P-K number, which indicates how much of the three major elements that plants need for good growth are contained in the mix.
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Vegetable Gardening & Fertilizer
The Best Fertilizers for Lawns- N-P-K Numbers
- By federal law, all fertilizer manufacturers must list the percentage by weight of nitrogen, phosphorus and potassium in the mix. This is expressed by three hyphenated numbers, such as 10-5-15, called the N-P-K numbers. N stands for nitrogen, P for phosphorus and K for potassium. Specialty fertilizers may have a fourth number, as well. For instance, a fertilizer intended to feed the grass and acidify the soil at the same time may read 20-0-0-25, the last number representing sulfur. If only three numbers are on the package, they always represent nitrogen, phosphorus and potassium.
- A fertilizer with an N-P-K designation of 12-12-12 is 12 percent nitrogen, 12 percent phosphorus and 12 percent potassium. If the bag weighs 10 lbs., that means 1.2 lbs. of each element. The rest of the mixture is made up of filler and trace elements. A fertilizer labeled 13-13-13 has 13 percent, or 1.3 lbs. in a 10-lb. bag, of each of the three major elements.
- By federal law, all fertilizer manufacturers must list the percentage by weight of nitrogen, phosphorus and potassium in the mix. This is expressed by three hyphenated numbers, such as 10-5-15, called the N-P-K numbers. N stands for nitrogen, P for phosphorus and K for potassium. Specialty fertilizers may have a fourth number, as well. For instance, a fertilizer intended to feed the grass and acidify the soil at the same time may read 20-0-0-25, the last number representing sulfur. If only three numbers are on the package, they always represent nitrogen, phosphorus and potassium.
Read more :http://www.ehow.com/info_8561856_difference-between-121212-fertilizer-131313.html
racerboy71
bud bootlegger
so yes, the higher the npk numbers, the higher the percent by weight each of those elements are present in the fertilizer..
That's a percentage of weight. It's useful to know how much actual fertilizer you're getting for your dollar. If both products were the same price, the 10-10-10 would be the better deal. You'd use less, it would last longer. (Baring other factors such as whether it's a brand name of generic, perhaps handled better. Remember, these are *minimum* percentages of weight. A generic brand could be sloppy when mixing, giving you 12-15-13 one time, 11-10-16 another. They could all be legally sold as 10-10-10. So, it's not entirely about higher numbers being better. Quality control might be an important factor. Respected brands being worth more than simply the weight of the nutrient.).
It's better to think of fertilizers as ratios. Both of what you mentioned are 1-1-1. A product that is 5-15-10 would be 1-3-2. A good veg ratio is said to be 3-1-2. A good flower ratio is said to be 1-3-2.
Sativied
Well-Known Member
Is in the US the weight always the weight of the contents of the bottle/bag or sometimes of the total amount of nutrients as well? In the EU 12-12-12 could contain a lot more NPK than 13-13-13, i.e. it merely says something about the ratio, not about the concentration.
StellerKeller
Active Member
Thanks. I was kind of thinking it was about ratios, but I see some that express 0.1-0.1-0.1, 2-2-2 or 10-10-10.
Seems that the suggested veg ratio, 3-1-2 and the flower ratio, 1-3-2, works out to 4-4-4, in the long run. Anything to say about that?
Seems that the suggested veg ratio, 3-1-2 and the flower ratio, 1-3-2, works out to 4-4-4, in the long run. Anything to say about that?
racerboy71
bud bootlegger
well according to this post..
those are just minimum % numbers, so that wouldn't really be accurate way of measuring the bags total weight ..
I understand other countries are different. Sorry for not thinking about that when I replied.
In the US: 100g of a fertilizer with 10% N contains 10g (or more) of N. Even a liquid fertilizer is represented this way. That's why liquid fertilizers in the US usually have the weight published on them. Without it, we'd have to add up the molecular weights to determine their contributions to the weight of 1 qt, for example, of pure water (which is a constant).
They don't accumulate like that, it's an average. For example, if you had 1lb bags of 10-10-10 and 7-7-7, and you mixed them together in a 2lb container, you'd have two lbs of 8.5-8.5-8.5. The 7 dilutes the 10, the 10 strengthens the 7.
Knowing this, you could buy an inexpensive 10-5-5 and 3-12-7 (just pulling numbers out of thin air) and mix them at various proportions to get something close to 3-1-2 and 1-3-2. (I created a spreadsheet to do this.).
However, I don't know how this works for anyone outside the US. I'm speaking strictly about the US's weight-based % system.
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