i used to let it stand around for a week or so ...

but i dont understand.. why you just dont mix half ... or just what you need???

to make half again ... just cut your fert to 1/4 per half gal???

ken

Thanks for the response Ken :)

I'm still experimenting with how to properly fertilize my orchids. I used to just pour the gallon mixture over the medium, much like when you water orchids under the tap. However, to me, it seemed like a waste....the water just ran through the pot and drained out immediately and I would use up the entire gallon. I just dont see how the plant could be properly fertilized like this.

So I decided to try a spray bottle. I make the mixture and soak the medium with the bottle until the water started to slowly drip from the bottom as opposed to just draining out. I figured the roots will be able to absorb the water better this way and its a bit of a bonus that I dont use as much of the mixture.

I actually dont mind making the gallon mixture and just topping up my spray bottle as needed. I'm just really curious to know if the leftover can be stored for a period of time and for how long.

If it is advised that storing the fertilizer for any length of time is a detriment, I'd certainly make an adjustment to the amount I make each time.

I too have pondered the proper way to fertilize orchids. Your experiment gives food for thought, no pun intended. I always thought the idea was to allow the fertilzer to flow through but never thought about the fact that most of it wouldn't get used. I hope others will chime in.

To spray is better than just pouring it on. Many roots do not go into the pot and there are mounted orchids too. The roots that you can see will turn green when fully saturated. If you spray and then come back a few minutes later you can increase the amount they will take. Also true in watering of roots you can see.

It seems that I frequently have leftover mix. I never throw it away. The longest I have kept it has been a couple of weeks. When giving orchids to newbies I throw in a gallon of my special mix. With one or 2 plants that gallon will last a long time.

While you are at it, when spraying you can add supplements or bug poison to the mix. But never use a spray bottle that has had weed killer in the bottle.

Some peoples spray full strength others do it half strength. The latter is also called spray weekly, weakly. I go full strength.

Liquid or powder fertilizer are a mix of chemicals. I was told, years ago by an someone in the chemical field that they keep forever. They are chemicals, like what you use in cleaning products. They do not degrade. Organic fertilizers degrade faster but even those keep 'almost' forever. I don't worry about it.

Products which have warnings about 'room temperature or exposure to sun' are products I will use quickly. Not fertilizer.

Jane

In my opinion the issue with keeping pre-mixed fertilizer is that it promotes a lot of other growth in your pump sprayer/watering can.

I water mounted orchids with pure RO water using a pump sprayer daily (with fert 1-2 times a month), but potted plants get watered with fert water 3 out of 4 times, they're watered heavily once a week usually.

IMO, fert is pretty cheap in the long run (2-3 tablespoons per week), so I try not to let that be a factor in my watering decision. Plus, my time is worth a little bit ;)

Bob

I don't keep fertilizer water for more than a few days. The Nitrogen would promote algae growth. yuck. I normally add some organic to the mix such as seaweed extract (like geritol for plants). That would be a smelly mess eventually. I use any leftovers to water the other houseplants or outdoor plants.
I mix small very dilute amounts and provide a spa bath for mounted plants. They are set in a bowl of fert mix of about a quart and allowed to sit and absorb for times of a few minutes to a couple of hours depending on the species and the type of mount. Cork absorbs and holds very little so a plant on cork (not my favorite material) would get a longer soak. On tree fern a shorter soak because the matrix of small twiggy stuff holds moisture well.

Some plants in baskets with dangling roots get hung up over the bowl of feed and the roots "sip through a straw."

In the summer outside, I mix a 10 gallon or more vat of organic fertilizer including seaweed extract and chicken manure, Epsom salts, boiled ground egg shells, and that is used for 2 or 3 (at most) days then the leftovers are used in the vegetable garden. I don't want any microbial growth that might promote rot.
Does that help any?
Cheers~
Maryanne in WMass

Maryanne,
I like your idea of a spa bath as long as they don't share the bath water. And sipping for dangling roots. I think it is optimum but more work than I want to do.

I also use a seaweed extract. I use a brand called maxi-crop. It makes a huge difference. I also add Magi/cal. a variety of important minerals. If there are algae issues I add an algicide. Be careful how much.

In my climate cork is a good substrate. It requires daily water. The roots seem to like to grab on. I jam in some sphagnum in to the crevices for extra moisture. It helps.

I keep a 1 gallon bottle with maxi-crop all the time. When it runs out I fill it again. it smells like the beach. Not bad.The seaweed juice is a root stimulant. I give extra to newly potted plants. Also I give it to injured or weaken plants. Not just orchids. Helps germinating seeds too. Tonic is a good description.

I like this thread. I have a bag of fertilizer that was given to me and I have no idea how old it is...When I mix it the color of it is definitely lighter than normal...I was wondering if it was even doing anything or effective. I also use the spray bottle method due to the amount of waste.