| A very good question. I was not aware there were so few choices in other areas.
you are right about the numbers. Nitrogen the first number is used to grow leaves, phosphate the second number for flowers and potash for roots.
I generally recommend a balance 20-20-20 mixture but the 18-24-16 is close enough. Peter's and Miracle Grow both make an all purpose fertilizer in 20-20-20 that is usually carried in all the big stores.
MOST IMPORTANT is that the level of fertilzer is too high for orchids. The recommendation for dilution is probably about a tablespoon per gallon for roses. (I personally do not like granular fertilizers- it is too hard to control the levels. I always use water diluted mixes)
Orchids get fertilized 'weakly weekly a weak solution of about a teaspoon per gallon not a tablespoon and used once a week.
Some packages are labled Orchid Fertilizer at 30-10-10. This is often recommended for orchids packed in bark especially as the bark gets older. As bark decomposes it uses nitrogen to break down. As a result 30-10-10 on an activily growing plant may really be closer to 10-10-10 for the plant and 20 nitrogen for the bark. It is not recommended for plants in hydro stones, sphagum moss or other none bark mixes. I use 20-20-20 for both my bark and hydro pots and they do excellant.
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jerry  |