Apple Tree in the Snow
As we are entering the hottest part of the year (in the northern hemisphere), I thought I would discuss a much cooler topic... Chilling Requirements for Plants.
There are certain plants that require cold temperatures to produce fruit. This is why, for example, apples are not grown much in Florida. Apple trees require a minimum number of hours below a certain temperature, and Florida just doesn't get cold enough for long enough. Now there are always exceptions to the rule, and certain apple varieties have been developed to grow in warmer temperatures, so if you live in southern California, you are not without hope for growing apples. However, we need to be aware of what our chilling hours are and what our plants need to fruit reliably.
Chilling Requirement is a term used to describe the idea that a plant needs a period of cold to blossom. The requirement is usually expressed with the interchangeable terms Chilling Units or Chilling Hours. One unit or hour is equal to one hour at or below the chilling temperature. Some plants have a Chilling Temperature that is below freezing, some others may need to be under 45 F (7 C), and others only need to be under 60 F (16 C) for example. Every plant has a certain chilling temperature. If a plant does not obtain its required chilling hours it either may not flower at all or will flower much less and therefore produce a lot less fruit.
How Ice Wine (or Eiswein in German) is made... seriously!
Now, there are two stages of chilling. I always consider the first stage of chilling to be like a baseball pitcher's windup. The first stage is reversible. As the season starts to cool down, the plant is getting ready for its period of dormancy. If the temperature warms up for a few days or a week or so, then the plant gears down from its dormancy preparation. It's like the pitcher stepping back off the mound. It's a do-over. No damage is done.
The second stage of chilling is like the pitch. It is the point of no return. It is irreversible. At some point (a certain temperature or a certain temperature for a specific amount of time), and this is very difficult to tell, a plant has committed itself to dormancy. Even if things warm up, the plant will remain dormant until other triggers cause it to break dormancy. If the temperatures are low enough for long enough throughout the winter, then the plant will be able to blossom well in the spring. If it is not a very cold winter, or if we have a plant that should be growing in a colder climate, then we may get little or even no flowering... and then our fruiting is poor.
It is important to know that the Chilling Hours do not need to be consecutive. Typically, the plant just needs cumulative Chilling Hours. We may have nightly temperatures that drop below the required threshold for our plant, but our days warm up above that temperature. If we have enough nights doing that, then that may be enough for most plants.
On the flip side, some plants have hair triggers to break out of dormancy. It the temperatures rise too high for too long, let's say in an uncommon warm spell in the late winter, then a plant will wake from dormancy and may start production of blossoms. When temperatures drop again, the new growth may be damaged or killed. This is what causes concerns about late frosts or early blooming plants in a garden.
Chilling Unit Map for the U.S.
So how does this affect us and our plants on a day to day basis? All it means is that we need to select plants that are suited to our climate. That's it.
Plants that have a Chilling Requirement to produce blossom well
- Pretty much all fruit that grows in a Temperate Climate (Apples, Blueberries, Cherries, Grapes, Peach, Pears, Plums, Strawberries, and many, many more)
- Oranges and other citrus (although they don't really go completely dormant, the chill produces more flowers and better tasting fruit)
- Many vegetables need some chill to produce seeds (Cabbage, Carrots, Celery, Sugar Beet, and many more)
- Almost all Bulb Plants
- Many seeds need a period of cold to sprout.
There's shocking news in the sports betting world.
ReplyDeleteIt's been said that any bettor needs to look at this,
Watch this now or stop placing bets on sports...
Sports Cash System - Automated Sports Betting Software.
Quantum Binary Signals
ReplyDeleteProfessional trading signals delivered to your mobile phone daily.
Start following our signals today & make up to 270% per day.
ReplyDeleteشركة نقل عفش
اهم شركات مكافحة حشرات بالخبر كذلك معرض اهم شركة مكافحة حشرات بالدمام والخبر والجبيل والخبر والاحساء والقطيف كذلك شركة رش حشرات بالدمام ومكافحة الحشرات بالخبر
شركة مكافحة حشرات بالدمام
شركة تنظيف خزانات بجدة الجوهرة من افضل شركات تنظيف الخزانات بجدة حيث ان تنظيف خزانات بجدة يحتاج الى مهارة فى كيفية غسيل وتنظيف الخزانات الكبيرة والصغيرة بجدة على ايدى متخصصين فى تنظيف الخزانات بجدة
شركة تنظيف خزانات بجدة
شركة كشف تسربات المياه بالدمام
شركة نقل عفش واثاث
شركة نقل اثاث بحائل
ReplyDeleteشركة نقل اثاث ببريدة
شركة نقل اثاث بالقصيم
شركة نقل اثاث بحفر الباطن
شركة نقل اثاث برابغ
شركة نقل اثاث بابها
ReplyDeleteشركة نقل عفش بنجران
ِشركة نقل عفش بحائل
شركة نقل عفش بالقصيم
شركة نقل عفش بالباحة
شركة نقل عفش بينبع
دينا نقل عفش بابها
اسعار نقل عفش بينبع
ReplyDeleteالبحث عن شركات نقل العفش بينبع
شركات نقل العفش بخميس مشيط
كيفية نقل العفش بخميس مشيط
اسعار نقل عفش بخميس مشيط
شركة ريلاكس لنقل العفش والاثاث
شركة نقل عفش بالطائف
شركة نقل عفش بالرياض