Which fertilizer?

[tucker85]

Originally Posted by orchidsamore

I am a commercial grower and try to eliminate Phosphorus from my plants as much as possible.

There is enough Phosphorus in Florida water that additional Phosphorus is not necessary.

There is no scientific proof that phosphorus aids flowers. A total deficiency will cause problems but that is almost impossible in Florida. There is scientific proof that Phosphorus kills beneficial microbes in your potting medium.

Phosphorus fertilizers are illegal to use in Florida during the rainy season if the water runoff can get into the ground water. Phosphorus is the cause of the destruction of the Everglades .

Plants absorb Phosphorus extremely fast. Studies at the University of Florida show that an orchid absorbs 50% of the Phosphorus applied in the first 20 minutes. It then takes 5 years for some forms to dissipate.

You should consider yourself lucky that you have not had bud blast like this in seven years. Commercial growers always have some it is part of nature.

This summer the heat variations and late rains have made everything difficult. My shade houses range from 70-105 everyday. It went from 40-104 everyday in the winter. Flowers can die in a matter of days after opening in this heat. The cold winter delayed blooming on everything. It has been a tough year on flowers.

I would stay with the low Phosphorus fertilizer you are using and stop worrying.

If you want to know more I will be reping the OurVitalEarth brand of organics at the Mounts Botanical Show September 11-12 in West Palm Beach. I will have many root displays of plants showing the benefits of different growing conditions.

The show is free admission and many of the best growers in Florida will be there. Dr. Martin Motes was a guess speaker last year (as was I) and he probably will be a speaker again.

Excellent information, Jerry. I will definately make the Mounts Botanical Gardens event. I wasn't aware of it until mentioned it. Thanks.

[tucker85]

Originally Posted by Ray

Jerry is right about the phosphorus demand of orchids - it is very small, and they store it away for later use.

There are three classes of uptake action and nutrient retention by the plants -

1. totally controlled by availability (concentration) and cell wall permeation,
2. that, like the phosphorus, that is controlled by concentration, then stored, and
3. ions that are actively "pumped" in by the plant.

Gloria - I cannot imagine what problems the use of RO plus the correct MSU formula would give you. I switched as an experiment, and my plants leaped for the sky. Can you tell us more about your feeding regimen?

Ray, thanks for confirming the information on phosphorus. I appreciate your help.