Growing Tender Bulbs in Cold Climates--Tow

Mary Sue Ittner
Mon, 07 Apr 2003 07:23:43 PDT
Dear All,

Mark Mazer sent the introduction to me for this topic of the week so I am 
posting it for him. It's a good companion to last week's topic for those of 
you who live in cold climates. Like Mark I hope a number of you will tell 
us if you try to grow tender bulbs, how you do it. It's impressive to see 
all the things that Mark in Zone 5 is able to grow.

Mary Sue
PBS List Administrator and TOW Coordinator

Mary Sue asked me to introduce the TOW: Growing Tender Bulbs in Cold 
Climates.  For the sake of this discussion, I will describe how this 
hobbyist is growing tender bulbous plants and hope that others will add 
their experiences.

Six years ago we erected a 12' x 24' x 9' aluminum greenhouse glazed with 
dual wall polycarbonate sheet (8mm). The ridge is oriented 
North-South.  Heat is supplied by propane gas. Costs have ranged from $300 
to $600 per year.  Back-up heat is supplied by kerosene heaters.  There are 
manually operated ridge vents and an exhaust fan on the gable end with two 
intake vents on the opposite gable.  Heat is set to go on at 40F, 
essentially keeping all parts of the greenhouse frost free, rarely will the 
coldest spots near the floor go below freezing. Fifty percent shade cloth 
is used from April to October.  The floor is stone dust.  Staging is welded 
angle iron topped with galvanized wire fencing cut and bent to go over the 
frame. Ten inch deep containers were made from HDPE sheet and filled with 
coarse sand to create plunge benches.

The winter bulb growing year starts for us sometime in mid September when 
that first cold front moves through and we water the pots.  Starting with 
only Lachenalia viridiflora the first year, there are now several hundred 
species.  Bloom begins with Syringodea longituba in October. Favorite 
genera include; Geissorhiza, Lapierousia, Lachenalia, Sparaxis, Babiana, 
Romulea, Moraea, Ixia and Hesperantha.  Most of the plants are grown in a 
sand/peat/perlite mix in deep square plastic pots (clay for those that go 
into the plunge) with a wad of long fiber sphagnum moss in the bottom.  We 
fertilize with an organic based bulb fertilizer before growth starts, and 
sporadically after that with Miracle Grow, seaweed or fish emulsion.  Pots 
are stored dry under the plunge benches, replacing the summer growers in 
dry storage.  Most of the blooming pots are densely packed together on the 
West side of the greenhouse creating a little patch of South African 
countryside. Repotting and most seed sowing is done during the summer.  The 
main disease that I have to contend with is botrytis; pests include aphids, 
mealy bugs, ants and scale.  Several cold frames are used for storage, 
acclimation, over-wintering marginal bulbs and for forcing tulips and 
daffodils for the house.
Summer bulb season starts in March when Arisaema and others that require 
dry winter storage come out from under the plunge benches.  Plants that 
don't like to dry out completely are stored under the staging and brought 
out as necessary.  Paris are grown under the staging year round as they 
have proved tender here during cold, open winters.

We also grow some Calochortus, Crocus, Cyclamen, Boophone, Androcymbium, 
Gladiolus, Gynandriris, Massonia, Velthemia, Watsonia, Wurmbea, Xerophyta, 
Zantedescia, Pelargonium (tuberous), Sandersonia, Alstromeria, Cyrtanthus, 
Narcissus, Fritillaria, Iris, Agapanthus, Clivia, Cypella, 
Amorphophallus.  Companion plants that do well for us in the same 
greenhouse include Vireya, Nematanthus, Cymbidium, Pleione, and a few 
alpines. Our 30+ year old Platycerium has a special spot. Visitors are 
welcome by appointment.

Mark Mazer
Intarsia Ltd.
Gaylordsville, CT 06755-0142
USDA Zone 5
Giant Schnauzer Rescue

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