do I stop fertilizing for winter if new growth is there?

[L-E-Mae]

I have a number of plants (dendrobiums primarily) that require a winter rest. I understand that I should decrease/desist fertilization and even water somewhere around "Halloween to Valentine's Day". But my question more particularly is: It's September 1, and as an example, my den aggregatum has 3 new pb's at about 1-1/2" long, and they'll be growing for quite some time. What's the general principle on discontinuing fertilization while new growths are starting/growing?

[Roberta]

If it is growing, fertilize. First, Dendrobium is a huge genus, and they don't all have the same requirements. Many neither need nor want a winter rest. Second, for those that do slow down in the winter, observe the plant. If it loses leaves, then you would stop fertilizing and water very sparingly (I have found that even for those, "no water" is too severe, in nature they get dew, so I water less frequently but don't completely stop) But let the plant tell you what it wants. But definitely, developing new growth needs both water and fertilizer, no matter what the calendar says.

[L-E-Mae]

That's how I felt (if it's growing, fertilize), and makes sense. I have a bunch of dens - and with such diverse needs - I could really use a spreadsheet to look after them! This happened last year - den aggregatum (lindleyi, I believe) started a flush of new growth (round 2 after a flush of spring growth) here at end of summer. I kept feeding the new growth. When it got too cold to leave outside (they summer outdoors at my house), I brought it in. But then I got no blooms, darnitall. I was afraid it was the continuous feeding/no real rest. I was determined to have a better go at the winter rest this year, so have been planning for weeks already. Total nerd, ha!

[Roberta]

Den. lindleyi used to be Den aggregatum... I have heard it called "Den. aggravatum" ... You might leave it outside a little longer... until night temperatures get down into the 40's F. At that point, fairly dry (maybe water once every couple of weeks) Problem with indoors is that it wants both bright light and a night temperature drop. Perhaps right next to a window, facing south if possible, would let it get cooler than the rest of the house and give the best light that you can give it.

[L-E-Mae]

Thank you for that - I will proceed. Is it fair to apply this same principle to my nobile? I'm in a similar situation. It put out spring growth, & in the last couple few weeks started a new flush of growth. I believe the nobile can take a cold drop too, maybe it can keep Den. lindleyi company out there?

[Roberta]

Originally Posted by L-E-Mae

Thank you for that - I will proceed. Is it fair to apply this same principle to my nobile? I'm in a similar situation. It put out spring growth, & in the last couple few weeks started a new flush of growth. I believe the nobile can take a cold drop too, maybe it can keep Den. lindleyi company out there?

Exactly. Den. nobile will benefit from the same "abuse". Those are not nearly as picky about blooming, in my experience.