Expert: Long Island Gardener - 2/17/2007

Question
Can you suggest a brand name for the fertilizer best for tuberoses?I bought 5bulbs which probably have multiplied by now, but I get only 1-2 stalks only.


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The text above is a follow-up to ...

-----Question-----
I bought tuberoses from one of the popular shopping channels about 2-3yrs back. I've planted them in a large pot. Since I've only got 2stocks of flowers in late summer. I don't know what is it that I am not doing correctly to this plant. It gets the morning sun and the late afternoon sun. I've been screaming for help everywhere, in vain. I love these fragrant flowers so please advice. I live in the San Francisco area, CA.
-----Answer-----
I had the same problem as you, Malabika, and I got so desperate I called Ralph Snodsmith on the Garden Hotline to get his advice.  He was somewhat helpful - recommended fertilizing (I realized I was using a high Nitrogen fertilizer, figuring "Fertilizer" is fertilizer).  I switched to high Phosphorous (N-P-K analysis is on all Fertilizer containers, you want the one with a high "P" in the middle and a low "N" and "K").

But there's more.

One thing these plant absolutely, positively NEED is FULL SUN ALL DAY LONG.  They take forever to spike and bloom - pot them up in April and May and you still may not see any blooms until October or November.  But boy are they worth it.  As you already know.

Since you are in San Francisco, you do not have the problem of keeping them outside until that happens.  But it is my understanding that S.F. does not get very hot in the summer.  Tuberoses grow faster in the heat, and they LOVE it.  These are Mexican natives; they are used to baking, bright, full, all day sun.

Get more sun to them - They will not give you a break on this.  Fertilize with high "P" fertilizer, which promotes blooming (instead of lush green leaves, which you are tired of looking at after 6 months).  They bloom once, then the fun is over for another year, so do not expect a re-bloom.  I like them so much, though, that I buy them by the dozens at wholesale prices.

Any questions?

Answer
Best fertilizer here is going to be good old American sunshine - as much as possible.  If this was a baked potato, you would want to turn up the heat.  Ditto your Tuberoses.

Peters makes a great high-potassium fertilizer for potted plants.  If you are growing these in the ground, make sure you incorporate a substantial amount of Bone Meal down there - you can't put too much in your soil and it will feed constant, steady molecules of Phosphorous to the roots of anything growing there for YEARS.  It is too late to do this for the plants you are already growing - just keep it in mind for the future.

But...

I do not know what your San Francisco garden centers are putting on the shelves right now.  In the East, and most of the rest of the country, you can't buy this at all.  They just don't have it yet.  So find a place that actually is selling it and follow these simple directions:

1. Check the N-P-K analysis on the fertilizer.  Every container has that.

2. Ignore the pictures and graphics on the container.  They will not necessarily reflect the contents.

3. Find an N-P-K number with a high middle/P number and low (or zero) N/first number (the last number is not usually important for your purposes here).

4. Use a VERY diluted fertilizer EVERY TIME YOU WATER these.

With extra sun, extra heat, and extra Phosphorous, I don't see how they can't bloom.

Please keep in touch.  Any more questions just ask.  I'd like to know how this works out.  Good luck.