Tag Archives: frost

Can Milk Jugs Help Grow Tomatoes?

Well, I’m trying something new in my greenhouse this year – milk jugs. Yup, milk jugs. Here’s the theory… All along my row of tomato plants are old milk jugs full of water. All day long the sun warms up the water in those jugs. According to science, water holds heat better than air. So when it gets cool at night, the air in my greenhouse will cool off much quicker than the water in the milk jugs. Thus, the heat in the milk jugs will slowly release through the night – heating the air around them. That means my tomatoes stay warmer longer. It’s kinda like a heat battery for greenhouses. The more milk jugs of water, the more heat is saved up all day and released all night.

So does it work? Well, I can’t really say yet. When I did my first thermometer test, the temperature on the ground six inches from the a milk jug was 0.6 degrees warmer than the temperature at knee height three feet away. So if warm air rises, the knee height should have been warmer. Tonight I’m going to take a another temperature test – one near and one away from the jugs – this time both at knee height. I’ll try to keep you posted.

I still need to seal up my greenhouse a little better so the warm air has a harder time sneaking out at night, so it’s hard to say if the milk jugs are really doing much good. But I’m pretty sure they aren’t hurting anything – at least my tomatoes aren’t complaining…. Take  a look!

Tomato Clusters

Nice, huh? Here’s another shot…

Heat Batteries

Has anyone else tried something like this? How has it worked?

Update September 28: Last night the temperature dropped to -4.7° C. Inside the greenhouse on the far side away from the jugs the temperature dropped to 0.2° C. But near the milk jugs the temperature got no lower than 2.3° C. So, I’m impressed.

When Can I Plant My Garden?

Well, it’s May and by now every gardener in Alberta is biting at the bit to get out there and plant their garden. Traditionally in these parts, gardens get planted on the May long weekend – this year landing on May 16th through 19th. Two years ago I planted my garden the first weekend in May and suffered no ill effects, but I don’t think I would dare do that every year. So what’s a gardener to do?

Find Your Frost Date

To start, find out what the ‘average last frost date’ in your area is. BE SPECIFIC. These can vary greatly from place to place. For example, Red Deer’s frost date is May 25. I live just 15 minutes south east of Red Deer, near Pine Lake. Pine Lake’s frost date is June 9th. That’s a whole 2 weeks difference!

And you can’t even guess based on north/south location. Hannah (south) & Edmonton (north) both have a frost date of May 10th! By the way, I think it is very unfair that Edmontonians (150 km north of me) should get to start their gardens a whole month before me! But that’s the way it is.

You can find the frost dates for your area at the Alberta Agriculture & Rural Development website.

Check the Forecast

Secondly, watch the long range forecasts for your area. I personally like the Environment Canada website, but they only forecast five days in advance. So for the long range forecast, I go to Accuweather Canada. They have a 15 day forecast that, of course, isn’t quite as accurate, but it gives you a good idea.

Guess, Hope, & Trust

All the averages and all the forecasts in the world will NOT guarantee that frosts or snow will not arrive after you’ve planted your garden. There comes a point when you just have to go for it.

For me, I’ve worked out a bit of a forumla: If it’s May, if the long range forecast has nothing colder than plus 2°, if it hasn’t pouring rain, and if I feel like it – then I plant my garden! Perhaps not the most scientific method, but thus far it’s worked for me.

This year things are shaping up to be ready to plant… [looking at accuweather forecast] Hmmmm. May 16th – the May long weekend. Go figure.