Let’s talk about greenhouse heating. We’ve done some very public studies and have said some things in the past. Let’s put some context to the discussion.
Last season, we put a concerted effort into heating our late season greenhouse. We pushed it to the point where we just didn’t want to afford it anymore. In the subarctic, there comes a point where the cost to heat exceeds any reasonable amount one might want to expend to produce quality home grown produce. And it happens quite quickly.
In that season, we reported net gains. And we were truthful. If you’re willing to pay $8 a pound for gourmet heirloom tomatoes, which is a fair (albeit ridiculous) going rate these days, you can definitely achieve a net benefit by paying for heat to prevent frosts. Again, to a certain point.
But, that’s not how economics actually work. An expense is an expense. In this case, we’re not buying gourmet heirloom tomatoes, we’re buying electricity. And in hindsight, that experiment translated to a rather expensive electricity bill. Yes, had we been buying tomatoes it might have made sense. But that’s not what we bought. Instead, we bought amp hours.
What we ultimately achieved in that experiment was more “vine ripened” tomatoes. Which, don’t get us wrong, we’ll sing the virtues of! But, a tomato harvested past the breaker stage will eventually ripen without any need for a vine, a greenhouse, electricity or any expense whatsoever you haven’t all ready signed up for.
Not to mention, we’ve all ready harvested a metric ton of our tomatoes. Sure, we can and will always find uses for more tomatoes. But, this perspective definitely influences the “value proposition” of heating a greenhouse and willingness to pay a higher electrical bill. It’d just be more of what we’ve had plenty of.
As for when we’ll shut our greenhouse down for the season? We watch things pretty closely and track our greenhouse temperatures. Once ambient overnight temperatures get to the point where we’d need heat, which for us is about 40 Fahrenheit, that’s when we’ll call it. For now, we’re still staying above 50F overnight, so we’re taking advantage of every bit of time we’ve got!
Ultimately, there isn’t a right answer to any of this. If you want to pay for heat, it will help you get a longer harvest period. If you don’t, you can ride out the natural environment as long as you can. Then again, you might be done with gardening all ready! We typically go right up until the snowfall!
Things are getting gloomy here, we’re definitely feeling those frosts coming on. The weather is saying we aren’t quite there yet, but our observations say otherwise!
