Expert: Long Island Gardener - 6/1/2006

Question
Good morning Expert.....
Whenever one purchases an annual at a nursery the young plant usually has a profusion of blooms on it.  After the plant is set in its new location and starts to establish itself (whether the location is a pot, the garden or a controlled environment like a greenhouse), the original blossoms die and new blossoms replace them.  While the new blossoms are loverly, they are usually not as large or as prolific as the original small plant from the nursery.  What does the original grower do to get those original blossoms.  Is it the mixture of nutrients, the growing media blend or some special tricks. Your advice is appreciated.

Answer
So, Stanley, you want to know the tricks of the trade that growers use to max out flowers before you buy them?

There's no real magic here.  

Growers protect their crops of Annuals heated under plastic or glass while the weather is still cold.  The combination of cool temperatures and protection from the elements creates the perfect environment for a flat of petunias or ageratums.

Cover your garden with plastic, turn down the air temperature, keep the soil warm, and with the right care your Annuals will look like they did when you first bought them.  Remember they still have to recover from the stress of moving out of their old nursery and into a new home, no matter how perfect the new home is.  

Further care depends on the plant.

Petunias and other Annuals don't do well with Nitrogen fertilizer.  I have a problem at my house because the soil is too rich in many places to grow them.  Overindulged petunias grow roots and leaves, not flowers.

To make the most of your Annuals now:

Feed with Superphosphate.  That nourishes the blooms and roots.  Size and shape are genetically programmed, but you'll maximize those genetic traits by perfecting the Phosphorous diet.  Phosphorous is the "P" in N-P-K.  Superphosphate is pure Phosphorous.  All plant "food" has a measure of N and K as well.  You want ZERO Nitrogen for most Annuals.  If anything, they got enough of that at the nursery.

Many Annuals do better in Heat and have to dry out completely between waterings.  Don't overwater them.  But don't underwater either.  Lack of enough water reduces the number and quality of flowers for many Annuals, but not for all them.

At the same time, drip irrigation is FAR SUPERIOR to overhead watering.  Most growers rely on drip irrigation systems for their flower crop; it's more economical, but even more important, this keeps water spots off blossoms and leaves.   

Pinch them as soon as the flower is spent.  Maturing Annuals need to branch.  I have been pinching my Petunias like crazy to keep them from getting spindly and to encourage branching.  I have Sweet Alyssum that I cut with a scissors to deadhead effectively so it still has a full season ahead.  

Which brings us to a VERY important procedure.

Deadheading should be done all season, on all spent blooms, as soon as the bloom is over and most definitely before they go to seed.  Dead and dieing blossoms emit ETHYLENE, which accelerates the aging process of flowers and fruits.  Ethylene is the stuff that's given off when fruit ripens.  You would put a peach under glass to trap the Ethylene and speed up the ripening of the peach so you can eat it.  Fruits, vegetables, car exhaust and cigarette smoke give off Ethylene.  While it's great to be able to ripen fruit at home, you NEVER want to do that with your flowers.  Some plants are VERY sensitive to Ethylene levels:  Achillea (yarrow), Snapdragons), Dianthus/Carnations), Alstroemeria (Peruvian lily) and Lilies.  Minimize exposure to Ethylene of all the flowers in your garden to keep plant hormones (auxins) from sending the message that the plant's services are no longer needed.  

Day length affects blooms.  Sunflowers and Zinnias set the most buds at day lengths shorter than 14 hours, for example.  Others are daylight-neutral.  

Make sure your Annuals are swimming in sunshine.  Almost always, these MUST have full sun to do their best.  

We're still in the Perennials season.  Annuals are best used to take over the summer garden after Perennials are done.  It's not summer yet!  

One last word.  There are some laboratory chemicals that can be used to increase the size of a blossom, sort of like steroids.  

But that's college stuff.  

You don't really want Monster flowers.  Just superstrong, superhealthy plants with turned-on blooming hormones.  

Now, if you have some specific plants in mind vis a vis this question, speak now!