New growth in winter. Should I increase fertilizer?

[lusenok]

It's winter in upstate New York, days are short and cloudy with little sunlight. But my cattleyas and oncidiums put tons of new growth. Growing tissue requires a supply of nutrients, right? Should I fertilize more now?

I heard many times that you are supposed to reduce watering and fertilization in winter, especially nitrogen supply, without a really good explanation why.
I see that my plants are putting couple of new p-bulbs each so I don't want to starve them.
What should I do?

Can cattleyas utilize nitrogen/phosphorous well without good sunlight? What kind of nutrients are stored in pseudobulbs anyway? This brings us to some fundamental biology questions. Maybe someone can help me with this

[tucker85]

If an orchid is growing it can benefit from fertilizer. Since the days are short and the light is less, it's best to fertilize at a low dose, maybe 1/4 strength.

The reason to fertilize less in the winter is that many orchids are growing very little or not at all. Therefore they won't use the fertilizer and it can start building up in the media. At high levels the fertilizer salts will start to burn the roots of the plant. Very often the symptoms of this will be brown tips on the leaves. Flushing the media occasionally with plain water can help prevent that.

The reason we water less in the winter is that the orchid is not absorbing as much water when it isn't growing. That means the media can stay wet too long and that can lead to root rot.

Orchids do store nutrients and, of course, water in their pseudobulbs and leaves. They can use those stored resources for a while but eventually they need to be replaced.

Now that orchids have been crossed with each other so many times some of them have evolved to a point where they grow all year. If that's the case, they can use a little fertilizer and water but not as much as they use during the long daylight hours of summer. By the way, some orchids like phaelenopsis and vandas grow continuously year round.

[james mickelso]

Follow Tucker's advice. The growth you see is coming from the store3d sugars and starches in the old pbulbs as the new growth doesn't yet have roots to take up nutrients in the water. Since there is little light this time of year, the old roots aren't absorbing much in the way of water or nutrients so fertilize at no more than 1/4 strength though I would cut that even more. Water only in the morning so that the media is as dry as it can get so you don't have bacterial and fungal issues. Give them as much sunlight as you can. At your latitude that can be full sun this time of year. Tucker is right too about the hybridizing. Most hybrids are really mixed up when it is time to put out new growth although many species do put out new buds this time of year because it can take 6 months or more to complete a new growth to flowering. I have most of my catts and laelias putting out new buds right now and my temps are in the 60's day and 30's night. I only water once every two weeks or so because they won't dry out. My bigger catts and cyms are still heavy and I watered two weeks ago. I only water those that have become lightweight. And the mounts and smaller ones weekly. Let us see some pics of your new buds.

[ginnibug]

Both of those were fantastic answers,just wonderful info, thanks so much. I have always wondered why this is the time of year for my catts to start throwing new roots. And they always do it in an abundance when you would naturally feel it was time for them to be resting.Ginnibug

[SlipperGirl]

What kind of fertilizer are you using?

[james mickelso]

I use a 30-10-10 Growmore fertilizer. First Rays has a good fertilizer that works well at making good roots. Talk with him.

[Orchid126]

Outdoors will be getting colder and colder since the first day of winter was only a few days ago. But perversely, the shortest day of the year was a few days ag. From now on the days will be getting lighter and lighter, if only by a minute a day. Many orchids respond to that minute change. Some of my cattleyas like to bloom during the first months of the year.

[james mickelso]

A few pics for the newer of us here to show how orchids grow. Catts and many other orchids put out growth buds at different times of the year. Some catts grow until almost mature before growing roots while others start roots halfway through their growth cycle. The new growth feeds off the stored sugars/starches held in reserve in the old pbulbs. This is transfered by water through the rizomes and that is why it is important to continue to feed and water although not nearly as much when it is cold. As your new growth grows you'll notice a shrinking of the older pbulbs and this is normal as it gives up it's stores of energy. They also lose some roots in the process because it is not actively growing. Roots start at different stages in different species. You just have to learn which does which. My Wilsonara here grows until nearly mature before growing roots. A couple catts here grow to maturity, flower, then grow roots. It is genetic and hybridizing really confuses the issue. I don't know how to post a pic and explain as I go but look at the pics and you'll see the evolutions. As a side note for those who saw my greenhouse before, well here is an after shot. Sold nearly everything and still miss them.But they went to a great home and the owner is really takeing good care of them. The first shot is new buds/no roots. The next couple are halfway through growing/no roots yet. The last couple are flowers/no roots yet. Then the last is Epidendrun "ciliare" which flowers this past summer and is just now growing roots. The last two are what was and is now. (tears up a little).

[james mickelso]

Sorry. Here's the Wilsonara. It will grow another 3 or 4 months before putting out roots.

[SydneyH]

Thanks for this information. I got a cattleya a while back at an orchid club raffle. It was at the end of it's blooming cycle and then the existing roots started looking not so good, or at least showing some wear. But right now it's putting out an abundance of new roots. It makes more sense now.

Sydney