It’s not uncommon for the temperature to reach 36 C inside during the winter.
However it is uncommon for there to not be any source for that heat other than the sun, but that’s exactly what’s happening in Wallace at Silvana Castillo and Heather Scott’s.
The women have been using a 20’x40’ passive solar greenhouse every winter for the past 20 years.
“Silvana had this vision to grow food in the winter using the sun,” said Scott, about her partner. “But at the time, nobody believed we could do it so it was hard to find a carpenter to help build it.”
The couple, however, found a professor at McGill University who had been researching passive solar greenhouses, and then Castillo had a friend design it. The greenhouse includes a brick wall along the length of it to hold the heat in.
“We have no supplemental heat – only sun – and there are only so many things you can grow without heat,” said Scott. “The question was can we grow food in the winter in Nova Scotia and apparently we can. We can eat live food grown in the ground, not hydroponically, and that’s a great thing.”
“The greenhouse has a foundation, so the soil doesn’t freeze,” Castillo added. “We believe that’s why it works. It can get very cold in here, but when the sun comes back, the plants come back.”
Over the past two decades, their success has been a lot of trial and error. Tomatoes were one thing the women tried, but decided not to continue with as they took up too much room.
Instead, it’s more cold hardy plants.
“We like the tastes of them,” said Castillo.
Arugula is one of the staples of the greenhouse, along with garlic, chives, parsley, peppergrass, shallots and herbs.
“We are seed savers, so we collect seeds for the next year. We select seeds from the plants that survive. It’s performed well,” said Castillo.
Castillo keeps a track of the temperatures inside and out. It’s reached a high of 36 C inside, even when temperatures outside have been in the minus double digits.
“Sometimes we can’t even be in here, it’s so hot,” said Scott.
One thing they had started using was a water pump, however freezing issues had them looking at other options. Now, they collect rainwater just outside the greenhouse, with pipe connecting to barrels inside. From there, they just plunk a watering can into the water to fill it.
“With rain, there’s enough melting and thaws that bring the water in,” said Castillo.
While many people garden in the summer, the greenhouse has allowed Scott and Castillo to extend the season. In the summer, however, the greenhouse isn’t used for growing. Instead, the outside panels can be removed, and the greenhouse becomes more of a sanctuary for wildlife.
Castillo said the summer is when the soil inside the greenhouse “rests.”
“We look after the seed crops and we mulch the grounds, but then we wait,” she said.
Because they weren’t strapped for space, the women decided to go large with the greenhouse. They were already having the foundation poured, so they decided to go for it instead of having it too small in the end. Over the years, Castillo knows the greenhouse has been worth it and has paid for itself through the nutritional benefits.
“We are strong believers that food has vitality,” she said. “We’ve seen over the years that there’s nothing to buy in the stores – it’s so dry and dead. Now, we have salads with every meal. It’s organic. It’s delicious. We love the salads, and we love being here too.”
“It has a restorative quality to me,” added Scott.
For their pets – cats and a dog – they also enjoy the greenhouse, especially the cats.
“We even have grass for the cats. When they come in here, everyone starts to run..in the rafters. They have siestas,” laughed Castillo.