how long I can use a diluted fertilizer? Algae fertilizer any good?

[epifit]

I own 1 orchid and I think it's a Phalaenopsis (white flowers)

I want to fertilize it. I have a 25-10-10 Orchid Fertilizer.
It suggests to dilute 1 teaspoon for a gallon of water. If I take half of recommended dose and mix it with water how long I can use this mixture?

I also read that algae fertilizer is good too, which one is better?

[Dusty Ol' Man]

One third of a tsp/gal should give you about 100ppm nitrogen. Used once a week this should last you a good long while depending on the size of the package. Use it till it's gone. If you use tap water with average hardness you shouldn't need to add any calcium or magnesium. Don't know about algae fertilizers.

[Dimples]

Maybe kelp fertilizer? Kelp products are typically used in addition to a complete formula. I think they’re better suited to outdoor plants, except KelpMax seems to be of actual value. I haven’t tried it yet.

[estación seca]

I think what you're asking is how long can you store mixed fertilizer. It should be good for several weeks, but store it as cool as possible. It is possible for fungus to grow on the surface.

The fertilizer dilution varies with how often you use it. The amount needed varies with how fast the plant is growing. Phals are warm growing plants that don't tend to grow much in a typical home in winter, so they benefit from more fertilizer in the summer and less in the winter.

What matters to the plants is the three numbers on the front of the fertilizer package, standing for percentages of nitrogen-phosphorus-potassium. All plants need nitrogen, potassium and phosphorus in fairly large amounts. They need other minerals in smaller amounts. Whether the nutrients come from kelp or from rocks doesn't matter to the plants so long as the quantities are sufficient. Most of the algae fertilizers I've seen have low numbers, so more would be needed.

Fertilizer is the least important aspect of growing orchids, after proper temperatures, lighting, watering and humidity. Almost any fertilizer with relatively similar numbers can be used. Fine tuning makes sense if growing conditions are otherwise excellent. It is better to spend time working on reaching the best temperatures, humidity, light and watering schedule.

[Ray]

From a chemical standpoint, it doesn’t matter the source of the ingredients, the ions absorbed by the plants are identical.

The claims made by manufacturers and sellers can get confusing. For example, there are products made from kelp that have been processed in a way that has degraded the more complex phytochemicals and rendered them no better than a fertilizer, yet they are claimed to be more than that. Then there are other products made from kelp that have been passed through a process carefully designed not to degrade them. They are excellent growth stimulants, but not fertilizers (although folks sometimes think they are).

As far as dilution of the fertilizer you have, it’s going to depend upon the frequency of feeding you wish to do. I have found that 75-125ppm N is a good concentration for plants fed weekly. If you divide 9.2 by the percentage of nitrogen in any fertilizer, the result is the ml/L for 100 ppm N, allowing you room to round up or down for measuring convenience. Your fertilizer, therefore, would require 9.2/25=0.368 ml/L, or 1.84 ml/5L, and I’d just round it up to 2ml. Putting that in imperial terms, 8/%N= teaspoons/gallon for 100 ppm N, so I’d go for 1/3.

If you feed every 2 weeks, double that, and if you feed twice a week, halve that.

[epifit]

The scoop that comes with the fertilizer equals to 1 tsb?

[estación seca]

There's a typo. Not sure what you're asking. The scoop holds 1 teaspoon (tsp)? or 1 Tablespoon (Tbs)? Does the label say to use 1 scoop per gallon of water, or 1 teaspoon?

[epifit]

It says mix 6ml per 5L or 1 teaspoon per gallon of water. It comes with a spoon. The spoon = 1 teaspoon?

---------- Post added at 07:02 PM ---------- Previous post was at 06:55 PM ----------

I went to the store and checked the composition of the algae fertilizer. The first 2 digits are 0% so it's not a very complete fertilizer. Maybe it's good to put time to time but not as a primary fertilizer.

[Ray]

Originally Posted by epifit

It says mix 6ml per 5L or 1 teaspoon per gallon of water. It comes with a spoon. The spoon = 1 teaspoon?.

How would any of us know that?

Have you compared it to a known measure?

[Arizona Jeanie]

Hello Epifit,
The measuring spoon that came with the fertilizer should be marked. It's not standardized, I have fertilizer with an included spoon that does not match the label directions, so I wouldn't trust it.
If you want half strength, get a set of kitchen measuring spoons, such as you'd use for baking. Then you could measure a half-teaspoon to add to a gallon, for a half-strength solution.
You could also just use one-eighth teaspoon, or just a small pinch, in one liter of water, and come out about the same. That way you'll have less to store.
The fertilizer itself doesn't go bad after it's mixed up, but, like anything else, it can support growth of algae, bacteria and fungi. As long as it looks clear and smells OK, I'd go ahead and use it.
Enjoy your orchid! I can tell you're trying to take really good care of it.