When to start watering--Second time around

I live in an area (the maritime Pacific Northwest USA) that typically has
no rainfall in July and August; this year there were only two rainy days in
September as well. However, October through May and often into June is
almost continually wet.

Most of my more interesting bulbs are grown in permanently covered cold
frames, in pots plunged nearly to the rim in sand. One frame has removable
covers that I put on only from about mid-November to mid-March; it holds
bulbs well adapted to the climate here, things I can grow in the open
garden but need to have a stock of for safekeeping.

I hand-water the covered frames on different schedules. Frame 1 is not
irrigated from about the end of April through late September, and often I
don't have to water it much during winter because the sand draws up ground
water, which penetrates the mesh and clay pots. I have a dry section
in Frame 4 that is managed the same way. Frames 2 and much of 4 are
watered more, including enough water in summer to keep the soil just
slightly moist. In Frame 5 I have a lot of seedlings, which I water some in
summer even if they are xeric species, in order to keep them from
desiccating while too small to recover from it. With them I have various
bulbs that tolerate summer moisture, and also one section for
summer-growers such as alpine Rhodophialas and lilies, which I don't water
in winter though they don't dry out, either.

I should point out that being plunged, the pots do not get hot and
desiccated as they would if kept above ground. Also, summer nights are
quite cool here, so the soil doesn't heat up a lot even in the frames. When
I lift the pots around the end of July, the bottoms are cool to the touch.

In order to decide where to put a given species, I read about its native
habitat. Sometimes I interpret this information wrongly and find out later
that I've misplaced it. If something doesn't thrive in one area, I move it
to another. The most useful books for this purpose are Martyn Rix's "Random
House [UK Pan] Book of Bulbs" and Brian Mathew's "Complete Guide to Growing
Bulbs," supplemented by field guides such as those by Oleg Polunin, and of
course the notes of the seed collectors who enabled me to grow the bulbs.
Even better is visiting the source area!

This is a lot of hand-watering, considering that the five frames are 40 to
44 feet long and 4 to 5.5 feet wide. However, I like taking the time to
observe the plants.

This year I watered a bit too early, with the first rain, because soon
afterward we had a historic record heat wave in late September. I kept the
pots moist, however, because I thought it would cool them down, and so far
things look all right.

It's true that you can retard growth by delaying watering, but I feel that
this can slowly sap the strength of the plants over several years. And it
can be death to tiny bulbs. I'd rather protect them from the infrequent
severe cold here, and have them flowering throughout fall, winter, and
early spring. However, this might not work for those in colder areas such
as the Northeast and Midwest USA, or Canada.

Someone mentioned avoiding getting water on the foliage of certain bulbous
plants from very dry areas. In the new issue of the AGS journal, Rannveig
Wallis mentions problems with Botrytis on foliage in their bulb collection
in soggy Wales. I don't have any trouble with this disease for some reason,
even with the wet winters, though I do try to water below the foliage where
it's feasible. The only Botrytis I have seen here has been on the very
leafy Fritillaria davisii, and on some Fritillarias I got from China via
Paul Christian (most of them died despite lots of spraying). However,
Botrytis paeoniae, which seems to have come here on some plants I purchased
from a Midwest grower, has destroyed many hybrid peonies in the garden, and
I no longer plant them.

In summary, I think most bulbs should not become bone-dry even while
dormant, but keeping them just faintly moist is tricky unless you plunge
the pots. (Using peat-based composts causes problems, too; I use forest
loam as the organic component instead.)

Jane McGary
Northwestern Oregon