Growing tomatoes outdoors in Scotland

Most tomato growers in Scotland grow theirs in their greenhouses because to be honest, our weather is unreliable in the spring and summer months and not always as warm as we’d like in early autumn. Which means, for warm weather crops like tomatoes, we can see poor harvests as tomatoes fail to ripen towards the end of the season.

But if you have cooler weather like me, you can try to get the upper hand by growing tomatoes with a “growing season” that matches the growing season for them in your garden. And you know what… it’s so much easier than you might think to work this stuff out.

So a bit of background then, tomatoes, as I’ve said are a warm weather crop. They really will not do well in temperatures below 15c and cold weather and frosts will kill them off. To ripen fruit, you will want your temperatures to be higher than 15c, pushing more towards the 20c. So you can work out how long your tomato growing season might be by looking at historical weather data for your garden (or area if you don’t record details for yourself) and decide when you think your garden gets a bit of consistency in the day time temperatures of 15c and above. It’s worth noting though, that your night time temperatures may still be too cold way later than you think. So check those too. I find by the second week in June my temperatures are fine during the day and not too cold at night, it usually doesn’t fall below 12c, so that’s when I say MY season starts. When does it end? Well doing this same thing, look towards the end of summer or beginning of autumn and watch for when your temperatures drop, again you are looking for the point when your temperatures are no longer consistently 15c and above. This is where you will struggle to get fruit to ripen on the plant, so effectively, the end of your season. There you go, count how many days you have between those dates and that is your season.

Now the next thing to know is that different tomato varieties have different seasons, yup it’s true, and so you can match the varieties you grow with your season. If you do an internet search for your variety and it’s days to maturity, that will give you good idea of the season for that tomato.

Now here’s a good thing to note, the tomato season or days to maturity is from small plant to harvest, not from seed sowing, so remember to add time to sow and grow your seeds.

So now that you are armed with this info, here are some of the varieties I’m growing this year:

• Black Krim 70-90 days
• Kellogg’s 75-90 days
• Gold Nugget 55 days
• Barry’s crazy cherry 75 days
• Sweet Millions 62 days
• Sun gold 65 days
• Black Cherry 64 days

So I guess the next question you have then, is when to sow your seeds? Well, again you need to think about when you can give those little plants temperatures that they will be happy with, although the good news is that small plant usually do fine with a slightly cooler temperature of 10c and above for those first few weeks. This means I can sow mine in the greenhouse from mid-March, but I may still need to cover those seedlings to protect them if we get some harsh March temperatures. For my plants that I intend to grow in the outdoors in the garden, I delay things slightly and I don’t sow until April again in the greenhouse, this allows the plant to get growing and become strong and healthy before I transplant it outdoors. I don’t want them to get too big before I plant them out as I don’t want them to get tall before they build up the strength to deal with the wind and I certainly don’t want a greenhouse bursting with plants I need to baby.

So have a think about your weather and what your growing season might be and then see if you can find some tomato varieties that might match up.