In your zone (5) you should be fine to start anything assuming you take the same precautions those up north do (Wall o waters, cloches, raised beds, starting seeds inside, using short season varieties etc...).

The general thinking for the ones south of us (zones 7,8,9 etc), is that if you start to late, the heat will kill particularly heat sensitive plants, or cause it to be so hot that a plant won't produce (aka tomatoes above 95 or 100ish).

So basically, if the DTM will still fit before your normal first frost - go for it!

Have fun.

I was wondering the same thing for my zone 8, because I wanted to try to plant squash late to get more production and miss the SVB...I actually think that I may have missed it or the worst of it, with the plants I put in late April early May.

I also just discovered that I have NO MORE squash seeds left, so I must get to Lowe's before it's too late and get some. Cant hurt, I figure, if it works then I get some extra squash, if not, oh well. I also have some climbing okra that I want to try, and I know it loves the heat. And my snap beans are producing like gang busters, but I've got room for more, and the package for those says to plant in intervals every 2 weeks up to a certain point before first frosts, well we hardly get any major frosts here, so that should extend them producing for a lot longer???

I think you're getting into the ideas behind succession planting. Particularly the type of SP where you sow another group of seeds every couple of weeks to get a continuous supply of a certain crop. Lettuce in particular springs to mind! I agree with jwstell42 that as long as your days to maturity are less than your days to first frost, you should be fine.

Down here I do worry about being "too late" with heat-sensitive crops like peas and broccoli. Up closer to you, my Mom worries about being "too late" with anything that needs a long season like winter squash. And to answer some of your questions, yes, they likely are selling short-season varieties. You can get them too, especially if you order seeds. I actually use a number of quick-maturing varities here because I do a different type of succession planting (small yard, long season) where I grow cool crops first, the pull them out and plant hot-season crops (and sometimes pull them out and do cool season crops again). I get my seeds for those from a company called Pinetree Seeds.

I get a really late first frost down here and the only other thing that can have a "too late" effect on certain crops is the fact that the trees to the south of my yard are fully leafed until sometime in November, so there's a lot more shade in the garden than in spring. So even though the temps are good for things like tomatoes, they stop producing due to lack of light. So, too late? Who says? :)

Cheers!

Sunni

Yes. Here in the southern zones the heat becomes an issue. Many things don't do well once nights become too warm -- over 70 for weeks at a time. Tomatoes, for example, won't set fruit then.

Day length matters too. Far north gardeners partially compensate for their short summers with the extra sunlight of their extra-long days.

I have a year-round growing season in my new home. But I'm learning that I can't grow the same things all year.

I have a spring, cool weather crop season that starts in Februrary and goes until late-April when the warm season begins.

The warm season transitions into the blistering hot season in mid-June then becomes a second warm season in late-July to early August in which I can grow peppers, tomatoes, and such things until frost strikes late in October.

The fall cool season begins in September and lasts through most of December. Hardy crops such as collards, some cabbage, and possibly other things that I haven't tried yet can be carried through the winter.

My official date for the planting of peas is January first.

The ground rarely freezes hard and truly cold temperatures last only for about 6-8 weeks from the end of December to mid-February.

Despite unusual amounts of snow this past winter I had cabbage loopers on my collards in January (I must see about floating row cover for those this year).

Once I learn how to manage the rotation I should be able to harvest all year. But what I'm harvesting will be highly seasonal.

Zones don't have anything to do with last frost date (planting time), only how cold it gets in the winter.

There is definitely a rough correlation between zones and first and last frosts.

IME, a lot of problems arise with most crops when planted very late. Of course, some of those have to do with crowding. But consider potatoes, for example. In z2 or 3 people are probably just putting out their seed. Planting potatoes here at this point would be a near-complete waste of time and space.

I'll give you rough, but that's it. Zones are set by how cold it gets in the winter. Period. My last frost date in Edmonton is May 7 (zone 3A) which is earlier than some last frost dates for places in zones 4/5. It gets damn cold here in the winter, but we have an early spring.

Pests and disease, in addition to frost, is a consideration to take into account when determining if it is worth planting something later than normal.

For example, turnips grow well here into the fall frost, but late in the season they often will be riddled with root maggots. Yuk!

Another thing to consider for fruiting plants, is the production window. I always work hard to ensure (semi-determinate/indeterminate) tomatoes have time to produce fruit for at least six weeks. Plant too late, and you get only a few tomatoes, before the cold weather stops the rest from developing.

Plant it. Don't worry about it. Use the extra space as a learning patch. So many micro-climates up here you may be surprised.