What do you think plants need to grow and produce food?
Where I live the last Frost date is May 13 but Everett closer to the water has a last frost date of March 23. You can learn your last and first frost dates (my first frost is Oct 5Th) a couple of ways. Washington State University hosts the Cooperative Extension in many county's here in Washington and they provide a valuable service including the frost dates. Sadly we may be losing these great services as the college has announced cutbacks on services. So don't wait to get information you need while it's easy to get. You can check with your local agriculture office or the college agriculture dept. Try online you may find your area on line. Know your city, and county.
OK put your thinking caps on and here is some other basic things you need to understand to be a good gardener.
1. Frost dates
3. Minimum winter temperatures
4. Accumulated heat units
5. Days of Sunshine
WOW just the list looks interesting doesn't it?
The city my frost date is listed with says last frost Mar 23. This never worked out for me and so I called the extension office and they told me why. I live in a mirco-climate. A little area with it's own climate. I'm on the East side of a hill and across from me is another hill. This pockets the air, cold, wet, snowy, what ever we get and give me a different climate than the norm. So are you in a mico-climate? See the list below for ideas:
A. If you live near a large body of water you are less prone to frost and often cooler on warmest days
B. Elevation, the higher you are the cooler and wetter in many parts of the county, surely here in the Pacific Northwest
C. If you live between hills as I do, cold air is more dense than warm and it flows downhill. That makes my springs very late and my falls very early. Study out the land around you! Is there a tunnel for wind?
D. North-facing areas receive less heat from the sun and southern exposures have more heat. This may change your length of growing season. North areas grow slower, Southern areas grow faster giving me time to grow things that take longer to mature (be eatable!)
Look around see what you have that might change your climate. Are there lots of dense trees? A large rock formation? Hills? Is your land East, West, North, South facing, where do you receive most of your light from? I'm at a disadvantage as my property is on an east Hill and doesn't get much of the western light, but I do get some Southern so that helps.*******************************
Minimum Winter Temperatures
There is a map that tells you what Zone you are in and what your low temperature is. It's wild to try to see the little bands of color and figure out what Zone you garden in.
http://garden.org/zipzone/ Try this web site to find your location close up. Also go to the home page for tons of great gardening ideas.
Each Zone designates an average annual minimum temperature.
Knowing your zone will only tell you the average least temperature.
I am in a Zone 7b with a mico-climate, the pacific ocean near by and lots of mountains. This means that in a zone 7b we get down to 5-10 degrees F. in an average winter with lots of other considerations. There are 11 planting zones across the U.S. and Canada. Don't place too much value on your Zone, they have to keep redoing these and there are so many other helpful considerations.
Accumulated Heat Units
Plants need heat to grow. We didn't have any heat last year and everyone had tiny carrots. They just couldn't grow with so few hours of heat. Plants require a certain number of accumulated heat units to mature. If you can't get enough of your accumulated (meaning over the growth period of the plant) heat you may not be able to ripen tomatoes, pepper, grapes etc.
Knowing this number can help you be prepared to trick Mother Nature. The right kind of plastic under tomatoes adds heat, putting peppers on the South wall of your home adds heat units. Lots of tricks to try and they do work.
Where I live in Western Washington we gets 1518 units of accumulated heat, where as over the mountains where the wheat grows they get 2,500 units.
OK some heavy stuff for serious people. 50 degrees F is the most frequently used base temperature for warm weather crops (I will cover those in another posting)
To figure the Heat Units you take the difference between the *mean temperature for the day and 50 degrees F. If the *Mean temperature is below the base of 50 degrees then there are NO heat units for that day. OUCH
Example: a day with maximum temperature of 72 degrees F and a minimum 50 degree (base) would put the mean temperature at 61 degrees. That makes 11 heat units added to the accumulated for that day.
(*Mean temperature is found by adding the maximum and minimum temperatures and dividing the sum by 2)
Now don't trouble yourself with this unless you find it fun but do know that plants can't mature for eating without a certain amount of accumulated heat!**********************************************
Days of sunshine
Because I live with a lot of cloud cover and moisture in the air I have a very low light intensity most of the year. What that does is make me consider where to plant things. Plants that do well in part shade may need to be planted in my full sun area's. This can affect food in several different ways. Apples may not get red, hot pepper may seem mild, peaches won't be as sweet and Vitamin C in plants will be reduced. You can compensate for this problem as you can for too much sun. Move plants into more protected areas and in partial shade. I have gardened in both kinds of climates and they have their blessing and challenges.