Expert: Long Island Gardener - 5/30/2008

Question
QUESTION: I live in in Alachua, FL area code 32615, we generally have 2-3 hard freezes per year.  This past yr I purchased tulip and daffodil bulbs at the local Sam's, I planted them in Dec just prior to our fist frost.  The results were dismal, not only did they bloom poorly but the tulips stems were only about 2 inches long.  I now realize it has something to do with the cooling period prior to planting in this zone can you instruct on the proper storage as the foliage has now died and I'm ready to store them...

ANSWER: Short stems MAY be caused by the wrong length or temps during cold storage -- or simply by fruit or vegetables in the fridge (they release Ethylene gas).  Or it can be the wrong micro climate.  I talked with a botanist about this who tried growing Tulips when he lived in southern New Mexico.  HIS Tulips -- when they flowered at all -- usually bloomed at ground level.  Never did determine conclusively if it was insufficient chilling; he was not ruling out the possibility that excessively strong sunlight kept the Tulips stems from elongating.

Another acquaintance in Southern California believes he owes all his Tulip blooming successes to correct pre-chilling.  Hybrids insist on a minimum of 6 weeks of cold fridge treatment, or you can kiss any decent flowering goodbye.  This is why it is so common for landscapers and other professionals to treat these as annual plants.  The second year bloom on bulbs left in the ground is ALWAYS a big disappointment.  Evidently Sam's supplier did not pre-cool them.  And that surprises me; these need to be professionally chilled for ALL Florida growers.  Most large bulb suppliers offer this service as an option when you place an order with them.

Serious hobbyists -- generally these are retired scientists and collectors -- can talk about this phenomenon for hours.  One guy kept a whole garden only of woodland wildflowers, and would wonder now and then why one particular Spring there would be a rash of specimens opening up no higher than at ground level.  His theory was that air and soil temps contributed, together, to keep stems from lengthening.  A sudden heat wave would zap buds as they were just breaking through the ground; wherever they were on the stem, that was where they would open.  And that was that.  When temps stayed cool, stems would be fine.

And yet another authority completely disagrees with him.  In his experience, a brutally cold Winter and Spring had the same effect, although he was growing other Spring Bulbs -- not Tulips or Daffodils.  He even monitored the temps through University of California at Davis -- a service the University of Florida does not provide so far as I know.  There is a factor that some consider called the 'DIF' -- which refers to difference in night and day temps.  'Positive DIF' means the day is warmer; 'negative DIF' means night is warmer.  Positive DIF gets credit for long stems.  Negative DIF gets the blame for shortening.

Your Bulbs -- Daffodils and Tulips both -- should be lifted and stored dry, relatively cool (but not cold) and totally dark, in a paper brown bag until September.  Then you can put the bag in the refrigerator for a month, and pot or plant them up as your local temps drop consistently into the 40s (does this really happen?).  Remember though that Tulips in particular are NOTORIOUS for being a one-hit wonder.  Re-bloom is the exception, not the rule.  Daffodils are much more forgiving, but some Daffodils are better than others for your Zone 8 climate.  Here's what your local Daffodil Society chapter advises you about these:

'...The best Daffodils for Florida are those from the Daffodil group called Tazettas.  These Daffodils have clusters of four or more (up to fifteen) small flowers on a single stem ...at least one parent descended from the species Daffodil N. tazetta –- the mother plant of all Daffodils with a lot of little flowers, usually fragrant, on one stem.  Many species tazettas are found in warmer climates around the Mediterranean, such as Italy, southern France, Spain and Portugal. This is why their hybrid offspring have acclimatized to North and Central Florida (and the coastal South in general).'

The Florida Daffodil Society website:

www.fladaff.com/

So you see there is quite a bit of science to all this.  Hopefully those were Tazettas you were growing and not Trumpets.

Although I realize it's easier said than done, try not to be disappointed with this experience.  Each try is a major lesson.  As you can see, not even the greenest thumbs, nor the highest IQs, nor the most experienced or specialized gardeners is always successful.  But they do always learn from them.  Doctors and Lawyers practice Medicine and Law.  We Gardeners are merely practicing Gardening.

THE LONG ISLAND GARDENER

---------- FOLLOW-UP ----------

QUESTION: How do I force bloom tulips?

Answer
One of the most important steps in Tulip-forcing: Select the right Tulip.  That means picking varieties that (a) have short stems (long stemmed hybrids bend and collapse when potted -- they are meant for ground-growing only) and (b) have a proven record of success (labelled "good forcers" if you're lucky in the catalog; others are prone to bud-blasting).

You also want to time your Tulips right.  This is an imperfect science, but as a rule, Bulbs planted in late Summer/early Fall take between 2 1/2 and 3 1/2 months to bloom; if you pot bulbs you received as a gift in December, they'll probably be blooming by mid-February or earlier.

Use a Clay pot for best results.  They're porous, so they breathe.  That makes anything you plant in them less prone to rot.  It's too risky to use plastic pots for Tulips, which spend months in very cool, wet, dark conditions with little air circulation.  Get the deepest pot you can find.  Put down a 5 to 6 inch bed of half sand/half potting soil, then place bulbs in a single layer, shoulder to shoulder, pointed ends up.  Cover the bulbs with another layer of Soil up to within an inch of the top edge, and water, letting excess drain out.

Now it's time for the cold treatment.

Tulips need 12 to 16 weeks of cold and darkness to grow roots and trigger flowering.  That means temps in the 40s ideally, but remember that any time the temps dip below that (or above 50 degrees), root development slows or ceases.  Refrigerators may seem foolproof, but their lack of air circulation makes it very hard to store bulbs in a wet environment without causing them to rot before the treatment is finished.

The odds get even worse when you start storing fruit in the refrigerator -- ethylene gas is emitted by ripening fruits and vegetables, and it damages Bulbs.

Check moisture levels occasionally.  If you're doing this in the refrigerator, which tends to be humid, the moisture will be constant.  But if you have an unheated garage you are using, or a site that is dryer, and the growing medium seems to be on the dry side, water -- probably once will be enough.  Studies commissioned by Peat growers found that Tulips forced with inadequate water tended to blast.  (Peat growers note that bulb rot is expected to decrease in Bulbs forced in Peat as a growing medium, but they learned that the acidity of the Peat keeps roots from forming -- keep that in mind if anyone recommends Peat for your pots).  Just be careful.

Once the big chill is over, you'll need a Sunny and cool, but unfrozen, spot to grow and bloom your potted Tulips, ideally 50 to 55 degrees F.  Two weeks of this treatment mimics the early days of a warm Spring day.  After that, your pots will need the brightest light you can give them.  We have an unheated basement with no light whatsoever.  For me, forcing pots of Bulbs involves bring the pots outside on unseasonably warm mid-Winter mornings and taking advantage of as much Sun as possible, then stuffing them back in the unheated basement or refrigerator at dusk to keep them from freezing.  For someone in a climate where children grow up never having seen a snowflake, special equipment may be necessary to get the chill that spring bulbs need.

That said, I can tell you that every tedious minute of care is worth it.  There is absolutely nothing like a collection of clay pots sitting on the front steps with flowers you have forced yourself.  A single pot as a gift is unforgettably beautiful.  A few steps of pots stop traffic.  Your mail carrier will love delivering your mail.  Years later, people will be admiring them from way back when.  In your case, they may still be wondering how you pulled it off.  This can be a great idea.

L.I.G.