Summer Greenhouse Tomatoes in Northern Minnesota

GeneMN · August 22, 2012

I have a graywater greenhouse where I grow tomatoes, peppers, and cukes in the summer, greens through the winter (a feat in northnern MN). They do well, but I'm noticing (2nd year) that they start to ripen later than field grown tomatoes. The season is deplorably short outside for any tomatoes, but it can be done here with WOW. I prefer to use my greenhouse, training them up ropes. Picked my last in November last year.

So my question is what might cause the later ripening? Maybe just the northern location? humidity? ????

Any advice appreciated. Thanks.

dokutaaguriin · August 22, 2012

Shortness of day and cool nights.

Jeff

GeneMN · September 17, 2012

hmmmm......from April through August the days are longer here than down south, and in the greenhouse the temps are higher than outside grown tomatoes further south. So I'm wondering if there could be something else going on.

ddsack · September 17, 2012

Interesting, Gene. The only thing that comes to mind is less light? Do you have trees that partially shade your greenhouse so that the tomato plants get full sun for fewer hours a day? I know that my back garden surrounded by woods ripens things later than the sun all day garden in front. After mid-August, the lower angle of the sun starts noticeably cutting down total sun hours over the tops of the trees as well.

GeneMN · September 17, 2012

That could be it. I only have 6 to 8 hours of solid sunshine, and that is interrupted by a couple of tree shadows. Nice to live in the woods, but....

ddsack · September 17, 2012

Sure sounds like it then. But late can be good -- if you can grow both inside and outside, you have a nice long season. We're supposed to get frost tonight, so if that happens, my tomatoes will be done.

nicky · September 18, 2012

I'm in Southern Ontario & have noticed the same thing. My greenhouse gets the same amount of sun as my outside tomato bed. The tomatoes in the greenhouse ripen about a month after (if not more) than the ones grown outside.

ddsack · September 18, 2012

I wonder if being under any sort of plastic or glass reduces the available lumens of direct sunlight by a percentage significant enough for the plant to need more time to ripen. You would think the higher temps in the greenhouse would compensate for the diluted sunlight. But maybe it doesn't work that way. Or could there be stress from too high a temperature in the greenhouse during the middle of summer?

August 22, 2012	#1
GeneMN Tomatovillian™ Join Date: Jun 2012 Location: Duluth, MN, USA Posts: 6	Summer Greenhouse Tomatoes in Northern Minnesota I have a graywater greenhouse where I grow tomatoes, peppers, and cukes in the summer, greens through the winter (a feat in northnern MN). They do well, but I'm noticing (2nd year) that they start to ripen later than field grown tomatoes. The season is deplorably short outside for any tomatoes, but it can be done here with WOW. I prefer to use my greenhouse, training them up ropes. Picked my last in November last year. So my question is what might cause the later ripening? Maybe just the northern location? humidity? ???? Any advice appreciated. Thanks.

September 17, 2012	#3
GeneMN Tomatovillian™ Join Date: Jun 2012 Location: Duluth, MN, USA Posts: 6	other reasons for late fruiting / ripening hmmmm......from April through August the days are longer here than down south, and in the greenhouse the temps are higher than outside grown tomatoes further south. So I'm wondering if there could be something else going on.

September 17, 2012	#4
ddsack Tomatovillian™ Join Date: Jan 2006 Location: Northern Minnesota - zone 3 Posts: 3,231	Interesting, Gene. The only thing that comes to mind is less light? Do you have trees that partially shade your greenhouse so that the tomato plants get full sun for fewer hours a day? I know that my back garden surrounded by woods ripens things later than the sun all day garden in front. After mid-August, the lower angle of the sun starts noticeably cutting down total sun hours over the tops of the trees as well. __________________ Dee **************

September 17, 2012	#6
ddsack Tomatovillian™ Join Date: Jan 2006 Location: Northern Minnesota - zone 3 Posts: 3,231	Sure sounds like it then. But late can be good -- if you can grow both inside and outside, you have a nice long season. We're supposed to get frost tonight, so if that happens, my tomatoes will be done. __________________ Dee **************

September 18, 2012	#8
ddsack Tomatovillian™ Join Date: Jan 2006 Location: Northern Minnesota - zone 3 Posts: 3,231	I wonder if being under any sort of plastic or glass reduces the available lumens of direct sunlight by a percentage significant enough for the plant to need more time to ripen. You would think the higher temps in the greenhouse would compensate for the diluted sunlight. But maybe it doesn't work that way. Or could there be stress from too high a temperature in the greenhouse during the middle of summer? __________________ Dee **************

August 22, 2012	#2
dokutaaguriin Tomatovillian™ Join Date: Feb 2006 Location: Alberta, Canada Z3a Posts: 905	Shortness of day and cool nights. Jeff

September 18, 2012	#7
nicky Tomatovillian™ Join Date: Jun 2011 Location: Ontario Posts: 600	I'm in Southern Ontario & have noticed the same thing. My greenhouse gets the same amount of sun as my outside tomato bed. The tomatoes in the greenhouse ripen about a month after (if not more) than the ones grown outside.