summer bulb storage

Jane McGary
Thu, 28 Jun 2012 10:14:08 PDT
Gastil wrote,
>How are winter-growing bulbs best stored in summer? ... Is it ideal 
>to re-plant or re-pot as soon as possible and leave in dry soil 
>until autumn? Or is it better to store them in a cardboard box 
>filled with wood shavings, vermiculite, or some other packing 
>material, or without packing material? I have an over-abundant 
>supply of wood shavings. rarely above 85 F. Is it better to leave 
>the dry leaves and stalks on the
>  surface for insulation or better to clear those away?

I live in a similar climate, and here is my experience. Replant or 
repot the bulbs immediately in fresh soil mix that is as dry as 
possible given your ingredients. Then replace them in their normal 
place, which one hopes would be a plunge bed in the case of pots. You 
can allow some winter-growing bulbs to dry out completely in summer, 
but some (e.g., many Narcissus and most Fritillaria) do best with a 
little sprinkle of water (not a soak!) every few weeks to keep the 
soil just barely humid. I clear the dry leaves and stalks away once 
they can be pulled free of the bulbs with very little pressure -- 
pulling them off earlier may pull up the bulbs or damage them. You 
can also cut off flowering stalks close to the ground if the sight of 
them annoys you. [Oh my, I see that my e-mail application is flagging 
"stalks" as if it is a bad word. It will also scream at me if I use a 
botanical name with the epithet "niger" in it.] I never used to mulch 
material in pots, but now that I have everything in raised beds, I 
use a pea gravel mulch.

Regarding the "baking" that Leo mentioned, this is a word you will 
find in British books, and it should be banned from the bulb 
literature. Few bulbs in nature "bake," because they are so far 
underground or are growing amid grasses or scrub. There are some that 
grow close to the surface in very hot climates (e.g., Drimia, which 
insulates its bulbs with deep layers of persistent dead tunics or 
leaf bases), but most escape the heat at the surface. The idea of 
"baking" bulbs seems to have arisen among English growers who are 
keeping their bulbs in pots in alpine houses, in a climate where 
summers are (or were. when they were writing) not very warm. They 
felt that the bulbs would not form flowering stems if not given extra 
warmth. This is not a problem in most of North America.

I avoid using bark or shavings with summer-dormant bulbs on the 
theory (intuitive but not by any means proven) that the organisms 
that decompose the wood products also attack the tunics (non-living 
tissue) of bulbs that have tunics. I have seen mycelia on bulb tunics 
that have been in soil including bark. This is why I always mixed my 
own potting soil rather than buying it, because it's very hard to 
find bark-free potting soil in this area (Pacific Northwest). Now my 
bulbs are all growing freely in pure sharp sand over a layer of clay 
and compost, and they seem to like it. However, you should never 
layer soil in pots because it will cause problems with watering, as 
detailed in the literature on growing alpines in pots.

As for Ruksans's method of storage, this is a common technique used 
by European commercial growers who need to have their bulbs available 
for shipping some time after they've been lifted. It may also be that 
he has to plant his bulbs unusually late in fall to prevent their 
emerging too early in his cold northern (Latvia) climate. Dutch 
growers do that with some bulbs from milder climates, such as 
Calochortus. Commercial growers do use wood shavings (pine, mostly, I 
think) to store certain kinds of bulbs and also to pack them for 
shipping, but remember that they (at least the big firms) have 
temperature- and humidity-controlled facilities for bulb storage. 
There is no advantage to the bulbs in being stored this way, except 
to protect them from summer rainfall in areas where that occurs.

When I was selling surplus bulbs, I kept them in a cool, dim room in 
paper bags, and I put some barely moist vermiculite around those that 
have no tunics (e.g., Fritillaria) or those that make root growth 
very early (e.g., some Narcissus species). They held well in this way 
for the six weeks I had them out of the ground.

Well, I am not an expert at the level of a commercial grower, but 
these techniques have worked well for me for 20 years.

Jane McGary
Portland, Oregon, USA

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