Fertilizer

[femin9]

Hello !
I have a problem with my orchids..I need a fertilizer and idk what to choose. I sow fertilizers npk , but in my country I can't find one higher than 7-7-7 . I know what each number means but idk what difference is between one 20-20-20 and 7-7-7.. Is a hogher one better?
Thx

[shushu45]

Sorry I don't know much difference in feritlizers. Hope someone who knows more can help.

[RandomGemini]

I think the trick is to get something that's balanced. The 7-7-7 would be fine, but it's not as concentrated as the 20-20-20 is, so you can probably dose it at the strength recommended on the package, I think. I'm still learning about fertilizers myself.

If my understanding of how these fertilizers work is correct, 7-7-7 is just a weaker version of 20-20-20.

[tucker85]

There's no difference between 7-7-7 and 20-20-20 other than the concentration. For instance if you want to use a concentration of 100 ppm nitrogen in a gallon of water it would take a little more than one teaspoon of 7-7-7 and less than half a teaspoon of 20-20-20. Try to use a fertilizer that also contains micro-nutrients.

[shushu45]

Originally Posted by tucker85

There's no difference between 7-7-7 and 20-20-20 other than the concentration. For instance if you want to use a concentration of 100 ppm nitrogen in a gallon of water it would take a little more than one teaspoon of 7-7-7 and less than half a teaspoon of 20-20-20. Try to use a fertilizer that also contains micro-nutrients.

Micro-nutrients??

[Ray]

Originally Posted by shushu45

Micro-nutrients??

Yes.

In addition to the macronutrients N, P, & K, plants need a substantial amount of Ca, Mg (often provided via hard water, if not in the fertilizer) and S, plus the "minor-" or micronutrients, Fe, Mn, Zn, Cu, B, Mo, at least. Others may include Si, Ni, Co, & Na, as well.

[femin9]

Well thanks for your explanations

[Optimist]

How do you know you need fertilizer?

[Ray]

The response time of plants - especially slow-growing ones like most orchids - makes a "visual feedback" way of management impossible. You're better off applying dilute fertilizer on a regular basis, and trying to keep track of long-term changes.