growing season zones rather than winter temperature zones

[digitS']

The lowest minimum winter temperature should be taken into account when purchasing perennial plants. The USDA hardiness zones are based on this idea. For example, I live in zone 5 according to the USDA. It wouldn't make sense for me to buy a tree that cannot live in a zone colder than zone 7. Temperatures much below 0F will kill that tree and my investment will be lost.

Hardiness zones, except by some great stretch of someone's imagination, have nothing to do with frost-free growing seasons. And yet, choice of annual garden plants is often dependent on the length of the growing season. For example, the last time I grew an 80-day tomato variety (Box Car Willie), only 1 tomato ripened on each plant . . . !

Wouldn't zones indicating the length of the growing season, as shown on this map, provide important information for most gardeners?

The accuracy project map appears to be based on the maps found at the National Climactic Data Center website. The NCDC zones are divided by 30 day increments to the growing season which make them more geographically precise. But, the absence of color in their maps also make them rather tedious to look at.

Steve

 

[Ridgerunner]

I'll agree it is a piece of the puzzle, but I'd think how important might depend somewhat on where you live and what you grow. For me, frost-free days are probably more important than freeze-free days.

The actual average or mean dates for last and first are important. Some cool weather plants don't take that long to provide a crop, like radishes and lettuce, and some can handle some frost or even a light freeze, such as beets, kale, chard.

Freeze-free or frost-free length of growing season will work with some crops, but some, such as pepper, sweet potatoes, and eggplant, need the ground to warm up before they'll grow, even if started indoors and transplanted. And some seeds, beans, squash, and corn come to mind, need the ground to actually be warm before they'll sprout.

And these are means or averages. This year, it looks like I'll get my first frost and light freeze tonight, 7 days before my mean first frost frost date. Of course nothing has been average about this year. Every year is a puzzle. This year completes my second growing season here and I learned a lot. I do not consider this a typical year and will not rule out my poor performers this year as typical for here. Last year, my spring broccoli did well. This year, it was a waste of time. I think it got too hot too fast. Then I had a cool, wet summer and a very wet fall. Not typical at all. I still based my planting dates on the mean dates. What else can you go by?

A piece of the puzzle, yeah. But for me, probably not a real important piece.

 

[digitS']

Winter loss of perennials must be not only more expensive but a more significant landscaping experience. But, I'm primarily thinking of the ratings seed companies provide for their annual varieties.

The days-to-maturity thing that seems so often to be based on whim rather than anything else, is a galling issue for me. I watched one cool year as a 73-day tomato gave me 3 weeks of ripe tomatoes while a 74-day variety was covered with green fruit right up until first frost!

Growing sweet corn, peppers, etc., etc. depends on some means to evaluate seed company offerings.

What is currently in use seems almost an absurd, random method of measuring plant development.

Steve

 

[Ridgerunner]

What is currently in use seems almost an absurd, random method of measuring plant development.

I fully agree with you on that. Like most things I see on the chicken forum, I take these things as general guidelines, nothing hard and fast or always accurate about them. I've planted two different varieties of sweet corn from the same seed company shooting for about 10 days difference in maturity to only have them ripen together. It made for a nice canning, but I also wanted fresh corn to eat on.

There are so many variables, rain, hours of sunshine in a day, number of days of sunshine versus cloudy days, air temperature, ground temperature, nutrients to name a few, that I don't think there is a simple method that works everywhere. Cabbage grows a lot differently in Alaska than it does here. I think the only way is to experiment under your conditions over a few seasons. This year taught me to not rely on one season of evaluation.

 

[bid]

number of days of sunshine versus cloudy days

This has had a noticeable effect on my vegetable garden this year. Several extended periods of either rain or overcast. An unusual summer to be sure. I had the worst tomato crop I can remember. I can only attribute that to temperature fluctuations early in the season and then the extended periods of lack of sunshine. But, next season will be here soon and present different challenges. On the plus side, I only found 4 hornworms this year. I think they might have felt sorry for me and those poor tomato plants?

 

[Greensage45]

Good post Steve!

Here in my region we have what we call 'Heat Factor'. Often amongst the gardeners and nursery folk we speak about how a plant performs at our highest temperatures.

Even though we are Zone 8a, the number of plants that should be able to tolerate growing here are reduced mainly because we exceed 110 for several weeks on end throughout the summer. In Phoenix it can reach in excess of 120; I don't know how those poor plants make it (that is my temp on my Compost Heap; I do passive composting).

I rarely look at too many "zone listings" on plants when I decide to plant. Instead I characterize the plant according to leaf-type, shape, growth habit, flower, color, and also water needs. Then I do a silly equation in my head and I begin to evaluate the 'micro-environments' that are present in my gardens. I do not often find the most suitable spot to plant because most times I dare not trust the full sun; eventually the plant tells me what it wants and I make adjustments. I do lose a ton over the years, but the knowledge and personal research is invaluable.

There must be a better way to chart and graph this for folks. I bet if you do they will name a day after you and everyone will forever call this the Steve Mapping Zone Growth Chart or something or other! LOL It would have to multi-tiered and multi-leveled. We might have to wait for Holographic Technology! LOL

Ron :tools

 

[digitS']

Oh Boy! I can be as immortal as sunlight. . . . shooting into space . . .

I want success in every seed packet! I'm too old to wait 4 seasons to find out if something works!

I bet heat is a serious issue in New Mexico. The American Horticultural Society has a Heat Zone Map.

Sunshine versus clouds is a big concern - our Puget Sound gardeners can attest to that. Do you know that they have only about as many growing degree days (warmth) as I do at 2,000 feet higher elevation and a much, much shorter growing season?

Using growing degree days that the Weather Service keeps track of for us, would make more sense for comparison of varieties. The seed companies actually use this for commercial choices but we are at the mercy of the propagandists with the catalog outfits.

Nevertheless, these heat/time units don't take into account sudden and short-term weather setbacks. Of course, nothing really can.

Not being able to time the harvest is one thing but I can only imagine how frustrating it is for new gardeners with small gardens to commit their space to something that is just doomed to failure because the chance to mature a crop was essentially ignored by the seed company.

Steve

 

[patandchickens]

Unfortunately I don't think it's possible to capture all the necessary info in just one or two numbers or maps.

It seems all too common for people to treat 'days to maturity' as some sort of fixed characteristic of the plant, when it's not, it is totally situation specific. Even at a particular site, a plant that takes 60 days from seed to harvest when planted in June will take a whole lot longer if planted in October. And different cultivars 'sulk' differently when stressed with coolth, heat, drought, etc, which of course will change the actual number of days to maturity that you observe in your plants.

The zone thing is actually simpler for perennials, IMHO, once you have some reasonable experience of your particular property. Very few have degree-day issues in terms of getting to flowering; the main thing is winter hardiness. And once you know your site's microclimates and how they tend to perform, and if you feel like mulching tender things, you shouldn't be losing *that* much over winter unless you are being *really seriously* bold with zones or have an unusually snowfree season.

The hardest thing to define zones for IMHO is woody plants, because microclimates (like cold pockets) and wind make so much of a difference to them, and they are usually a considerable investment of both money and growing-time.

Pat