Fertilizing now that it's cooler.

[Paul Mc]

As some of you know, I never fertilized until this year. I am thoroughly impressed with the new growths I've seen and have even gotten somewhat have never bloomed before to start spiking!!!!! I'm sooooo excited.

But, now that the weather is cooling down I'm curious how much to cut back. I've been fertilizing my potted orchids 2 weeks weakly with 1 week off. My mounted ones were getting fertilizer maybe twice a week. I know I need to cut back now but unsure how much to do so. As in 1 week fertilize and 2 weeks off for potted and maybe weekly for mounted?

[Cym Ladye]

I am assuming from your location that most if not all your plants are grown in a greenhouse or indoors. With the exception of those plants which need to be dried off during the winter, the general rule of thumb is fertilize weekly/weakly. You have been skipping a week, which is OK if you feel you need to flush out excess salts from your water source.

As temps cool down and daylight hours decrease, water as needed but each time add fertilizer diluted 1/4 to 1/2 the recommended strength or 1/2 what you have been using during the warm months. Phals prefer a dilute fertilizer all year long so this is more a rule of thumb. This works for the MSU formula as well as the bloom and equal ratio fertilizers.

Cym Ladye

[Bill U.]

Depending upon the types of orchids that you have- some need essentially nothing during the winter, while others like fertilizer all year long.

Phals and phrags love to get all year round. I use the suggested "portions" from Ray:

Fertilizer Mixing Calculators

Fertilizer PPM Calculator

When I talked to Ray, he said that using these ratios, phals would thrive all year round (on a 1 out of 4 waterings flushing schedule) without having to ever switch to a "bloom promoter" fertilizer.

My rule of thumb is to follow Ray's ratios according to the specific culture guides of my plants (basically I give each one a look up and many times there are suggested watering/fertilizing guidlines for winter/cooler weather).

[magicatt]

Since things in my growing area have slowed down, I have cut my fertilizer by half. They are still getting some just not as much as before. When I start seeing new leaves and roots again I'll up my dosage back to where it was. My two cents for what its worth.

[Paul Mc]

So, my assumption to use 1/4th recommended dosage during growth cycle was wrong? Should I have been using full dosage and only 1/4th now, or are you saying 1/8th now?

[NYCorchidman]

Plants that continue to grow during winter time, continue to feed. Ones that rest or slow down during the winter, cut back on feeding.

I don't change the fertilizer dilution in the winter, but just the frequency of fertilizing for the ones that do not grow much during the winter.
like from every watering to once or twice a month.

[Masdyman]

Keep it simple by using a feed you can use all year round like MSU and at a strength of about 70 ppm N, from there I just feed at every watering.
Feed at every watering sounds scary for some, especially in winter, but if you think about it, some orchids like Cattleya will not be watered much if at all so will hardly get feed compared to say Phalaenopsis or Masdevallia which require watering year round.

[tucker85]

Try to get to know your orchids needs. Some orchids, like phals and vandas, continue to grow in the winter but more slowly since the daylight hours are less and the temperatures lower. I usually go from fertilizing every week in summer to every other week in winter. Other orchids like some cattleyas and dendrobiums often have a long rest period where they don't do anything. I prefer not to fertilize them at all if they seem to be resting. If they're continuing to grow I'll fertilize either once a month or every two weeks. You won't force an orchid to grow by fertilizing it, but if the plant isn't taking up the nutrients the mineral salts can build up in the media and become toxic. For that reason, in the winter, it's even more important to flush the media real well about once a month.