USDA Zones on the database

Not a complaint, just a query.

I'm having trouble with the USDA zones on the database. As you know our zones in Europe don't really equate with the heat, rainfall and length of seasons you have there.

I know whats hardy here in my garden and area, it ranges from alpine plants to bird of paradise overwintering with some mulch but I don't feel I can accurately fill in the zone part of the database.

Is there a comprehensive site on this somewhere?

Baa,

The USDA Zones don't mean anything when it comes to climate things like heat, rainfall, and season length. All they do is tell you how cold you can expect it to get in the winter.

To determine the hardiness of a plant (in terms of USDA Hardiness Zones), you can lookup the minimum temperate in which a plant may survive. Then match that up with the zone, and you've got your zone infos.

Or, just leave it blank and someone else who knows can come behind and let you know what to put in there.

Dave

I'm intrigued by Baa's question - IS there any known movement to create a universal codification of climate? So whatever my high/low temp; rainfall; humidity; first/last frost, etc all become a numerical rating, which could be understood and related to by everyone else in the world? (And vice-versa, of course :)

vols: I've searched and searched, and have yet to find anything on this. I've had discussions with other DG members in the past about setting something like this up ourselves, but the work involved would be an incredible amount.

But... it is do-able. Taking into account the factors that you mentioned, and making it into something like a 4 digit "zone", which can then be mapped against other zones to find out how similar your climate is to another zone, would be EXTREMELY useful.

In fact, it gets even more useful as the world gets smaller and people start trading plants and seeds with folks around the country and the world.

What an investment of time that would be, though, and it would really only be valuable if EVERYONE started using it, including seed companies, educational institutions, the USDA, and such.

What we have now is a hardiness map, which is basically useless for determining your climate.

Dave

Has anyone heard of the new heat zone map designed and utilized by the American Horticultural Society? Seems if it were more widely used, it would be just as helpful as the USDA. Premise of the new zone map is that heat tolerance is just as important as cold hardiness to gauge the success or failure of planned additions to the garden. Their zones are rated as to how many days your area can typically expect to have temperatures above 86 degrees.

There are some nurseries which are using this guide but unfortunately it is not very widely utilized. Perhaps this might be a useful addition to our data base.

Thanks for the clarification Dave.

Plantman

I agree that heat is an important factor, particularly heat tolerance.

Rain/winter wet tolerance is an important factor for those of us in the UK and Western Europe I have added in the General Description where plants do not tolerate winter wet.

I think the problem with an all encompassing Zone/Climate chart is that it would be very confusing (certainly for me).

I think I'll stick with putting as much growing information as I can in the general description for now.

Plantman, I debated with myself on whether to ask Dave to include the AHS zones as dropdown lists when we added the USDA zones. But until they become more widely used, I fear they would add more confusion than they would eliminate.

Baa, let's think about this from another approach - we have listed the plant's moisture requirements - drought tolerant vs. average water vs. needs constant moisture vs. suitable for pond/bog. But these are addressing soil moisture, and you are referring to humidity levels.

Perhaps we need another set of radio buttons to indicate if plants prefer/require moist, humid conditions or dry, arid conditions, or something in between? Something to consider for all of us - what are everyone's thoughts on this?