The pictures above and below were taken March 8th. At this time the previous four years we had the hoop houses covered with poly and little seedlings were emerging. Not this year!
While much of the nation has experienced record high temperatures over the past month, and spring is arriving earlier then ever, our corner of the country remains cool and wet. I’m not complaining; every year with a good snow pack and normal or late spring means one more year with water in the rivers and flowers in the hills. These conditions are all the more precious as with global warming we are seeing less snow and longer, hotter summers ( and more wildland fires, fish die offs, irrigation problems and much more).
Still, plants will grow and we plan to be open for retail customers on Friday, March 31st, and will be open Fridays 9-5 and Saturdays 8-12N through June.
Our new greenhouse became operational in December 2016 and we quickly filled it with plants. We have heated beds that we use to root several species over the winter; below you can see plants that were rooted and recently potted up of mountain boxwood (Paxistima myrsinites) in the foreground with twinflower (Linnaea borealis) behind.
The greenhouse also allows us to get a jump on growing several species from seed. We are trying to get 36″ tall trees by fall of mountain alder (Alnus incana) and water birch (Betula occidentalis) so I germinated seedlings of both species in late January (below).
Most seeds of native plant species need a period of cold treatment in order to germinate in the spring in good numbers and within a condensed period. The seeds need to be moist and held between about 32F and 36F. For most species, we do this by sowing them in flats or containers in a moist media in the fall and setting them outside to be covered by snow. The latent heat in the ground and the insulation provided by the snow generally keeps them in the ideal temperature range. Pictured below are trays of 10ci tubes sown last October with bitterbrush (Purshia tridentata) seed; as soon as the snow has melted, and we’ve covered that hoop house, they’ll be popping up.
Most of the heat of the new greenhouse comes from the sun but is supplemented by warmth drawn out of the ground through a series of pipe manifolds we buried at 24″ and 48″ below the floor. When temperatures drop to a certain point at night air is circulated through the perforated pipe, bringing warmer air out of the ground. The same system cools the greenhouse during the day, bringing the cooler, drier air out of the ground when the high temperature limit is met. With this GAHT (Ground-Air Heat Transfer) system, and by insulating the mass of soil below the greenhouse, the temperature at depth remains in the 50’s all year.
What you don’t see is me off to the left, soaking up the warmth in a comfortable chair, book in hand, while the snow falls outside (!)
THINK SPRING (officially, only 11 more days). Before long we will be seeing…