Cold Spin

The first half of 2014 may go down in the history books as one of the worst winters in years. Everybody is tired of all of the cold and snow and any of the other four letter words you can associate with winter. All my gardening friends are really getting the fever to go out and do something, anything, in their yards. As depressing as this has all been, I wanted to try and put some good spin to the benefits of this nasty weather. I also wanted to discuss what you should and should not do to your cold damaged plants.
Let's start with the temperatures and chill hours. These are calculated by how long the temperature is below 45 and above 32. There are many plants that need lots of these type of hours to have a good fruit set. Apples, Peaches and Plums are some of the ones that most people think of off the top of their head. Did you know that brambles (Blackberries, Boysenberries and Raspberries) need chill hours also?

If you want to learn more about Brambles and growing them, check out the article I wrote a few years ago HERE
 So with all of the cool and cold temperatures we have had, it ought to be a bumper crop of a lot of fruits. There are some fruiting plants that don't like the cold however, and because of when they flower and start to set fruit are probably a total loss this year. Here in the Charleston, SC area, the Loquats are pretty much toast, but this is suppose to be an article to spin the cold good, so we won't dwell on them.
Moving on to other aspects of what the cold has done.
For those of you that hate to prune or just can't seem to thin out the number of plants that you have, this has been your winter!
I hate pruning. I do it if I absolutely have to, but I find it hard to cut off parts of a plant that are still growing. This winter has fixed that problem!!
With that being said, I don't recommend doing any pruning until it starts to get warm and STAYS warm. The reason I say this is because you don't know how much to cut yet. You need to cut off all of the dead wood, but you don't want to cut off too much either. The number one question I have been getting is, "Should I cut back my dead looking Citrus tree"?
NO!! Not yet.

If you grow any citrus trees, they probably look like the one above. Don't panic! They are still alive. If you want to test and see, scrape the bark in a small area and look for green. I know this is hard to see, but kind of like this:

If you look at almost the very center of the picture, you will see a small scrape and green. This one is going to be fine.
If you do find brown, go down about 6 inches and do it again. Keep going until you find green. If you get to the bottom and still nothing, all hope may not be lost. The rootstock may come back and give you something new. It may not be very tasty, but there would still be a plant there. Incidentally, this will work for pretty much any plant.
As for the thinning of your plant collection. I admit it, I am a plant whore. I have many, many plants. Probably more than I really need, though, when is too many reached? This weather has definitely killed off a bunch of my "borderline" for this area plants. Do I restock or do I just go with what I have, time will tell. In the meantime, I will be able to pay more attention to the ones that survived.
Okay, that gives you a little hope from the cold.
What about the snow and ice?
The ice will actually protect the plants from the wicked low temperatures. Down in Florida, they use ice as insulation from the extreme low temperatures.

How it works is best described here from the Florida Extension Services:
"Cold protection with sprinklers: The principle behind the use of sprinklers to protect trees from freezing is that heat is released when water changes from liquid to ice, a phenomenon known as heat of fusion. When water is freezing, its temperature will be near 32 degrees F; therefore, the heat liberated as the water freezes maintains the temperature near 32 degrees F. This temperature, known as the triple point, is in equilibrium between vapor, liquid and ice. If sufficient water is applied, and all leaves and branches are covered with ice, protection can be expected. If only partial coverage of leaves or branches is accomplished, damage can occur, and the damage will be more severe than if water had not been applied. Do not stop sprinklers until the temperature is 32 degrees F or above and water is dripping from all parts of the plants."
Wow, that was intense! I hope you got the gist of that?!
I don't recommend this to homeowners, I don't even do this. There are many factors that can go wrong. It can break branches. You end up using LOTS of water and flooding your yard, the neighbors and half of the neighborhood. Like the extension said, if the coverage is not complete, damage can still occur. So for us hobby growers, it is just not feasible. How does this tie in to a good spin? Mother Nature is providing the ice, so maybe it will prevent further damage.
The prediction of snow usually has a lot of people freeking out. Yes, driving is treacherous, schools and such close, but for us gardeners, it can be a good thing. Have you ever heard of Poor Man's Fertilizer?

That is how I try to think of snow. Rain and lightning contain even more nitrogen than snow does. But snow has the fertilizer reputation because it feeds nitrogen to the soil slowly over time at a rate it can be absorbed. As every school kid knows, the atmosphere is 78% nitrogen gas (N2), which is a compound made up of two bonded nitrogen atoms. It’s easy to assume the N2 is what comes down to the ground in precipitation, but that’s not quite right. Nitrogen exists in numerous forms, and N2 isn’t directly usable by plants. It needs to be first converted, or “fixed” into mineralized nitrogen forms. These forms are suspended nitrogen compounds such as nitrogen oxides, nitric acid, and especially ammoniacal nitrogen. These compounds find their way into the atmosphere from the burning of fossil fuels. It is estimated that since the industrial revolution, the nitrogen content of precipitation has increased dramatically. Who says pollution is all bad?
I hope I haven't gotten too technical and this was easy enough to understand?
But, as you can see, cold, snow, ice and all that other crappy weather associated with winter may not necessarily be all bad. There might even be a little good coming from it.
I still think winter bites, but at least I can take some pleasure in knowing that, in the long run, my garden and yard will be better off for it.
As always, if you have any questions about this article, or anything else gardening related, don't hesitate to ask. I can be reached through this blog OR TheCitrusGuy@netzero.com
Happy Growing!
Darren 

Cold Damage Identification and What to DO about it

The past month or so, I have made numerous blog postings about bringing in your plants and protecting them from the Winter weather. If you missed either of these postings, you can read it HERE and HERE .
Today I am going to talk to the people that, for one reason or another, didn't bring their plants in or try to protect them. They may have missed the weather report, forgot about their plants, or didn't want to take the time to do it and now their significant other is upset because the plant looks dead. There may be hope!
You will need to ask and answer a couple of questions: How cold was the temperature? How long was the plant exposed? What was the health of the plant before the damage?
First, let's take a quick look at what cold weather is and how it can affect plants. I know, duh, it's cold, they freeze! Well, just follow me for a minute.
The sun warms the soil surface during the day; the heat is then radiated into the cool atmosphere during the night. The coldest temperatures occur about daybreak.
Clouds at night can absorb and reflect heat back to the earth.
Calm, clear nights pose the greatest danger of frost since there is no wind to mix the ascending warm air with the descending cold air, and no clouds to radiate heat back to the soil.
Cold air settles downward, flowing like water,to the lowest point. Hot air rises.
The effects of temperature vary with plant species, stage of growth, age, general health and water content. Young, actively growing, flowering, and/or dehydrated plants tend to be most vulnerable.
Freezing temperatures damage plants by rupturing plant cells as ice crystals form and rapid changes in temperatures occur. Evergreen plants can suffer damage from blowing Winter winds and dry out when water is unavailable from ground that is frozen. Chilling injury can occur to many tropical plants although temperatures do not drop below 32 degrees.
The signs of cold damage can be confusing, since some damage may not be evident until months later. Leaves and tender shoots subjected to freezing temperatures or chilling damage appear water soaked and wilted. These tissues will usually turn black within a few hours or days. The tips of narrow-leaved evergreens, such as junipers, may turn uniformly brown. Broad-leaved evergreens, such as hollies, often have leaf burn along their edges. Less flowering is common during the following season.
One of the main things to remember is Do NOT prune frost-damaged, woody growth until the plant begins growing in the Spring. Pruning might stimulate new growth which would be vulnerable to late frosts. The frost damaged leaves and stems will continue to help trap warm air within the canopy. This is especially true in very large leaf type plants, such as Bananas. In addition, the damage is often not nearly as bad as it initially looked, new growth may come out of tissue that you thought was dead. Once the new growth starts in the Spring, you can prune out the dead wood.
A large, deep, crack running up and down the trunk of a tree or large shrub is known as a frost crack. The crack is usually on the South or Southwest side of the trunk, but can occur on any side. Young trees or older trees with smooth bark are the most susceptible.
Frost cracks occur when the sun warms the trunk in the Winter, causing tissues to rapidly expand or when clouds or buildings block the sun. At sunset the temperature of the trunk drops quickly to that of the surrounding air, and the trunk contracts. The outer part of the trunk cools and contracts faster than the inner tissues. This difference in contraction rates can cause the outer trunk to crack. You can usually eliminate this problem by wrapping the trunks with burlap or some other type of protection, not plastic, it needs to breathe. Start at the ground and work your way up to the first branch. Prevention is important, once the crack occurs, there is not much that can be done. Such frost cracks often close and callus over during the Summer, only to reopen in following Winters. This callusing and recracking may lead to the formation of large "frost ribs" on the side of affected trees. Something else to keep in mind, insects like to find places to hide and a large split open trunk is basically a "We'll keep the light on for you" sign. You could be looking at a major infestation. Frost cracks in trees are also ideal sites for the entrance of wood decaying organisms.
Desiccation, or drying out, is a particular problem on evergreen plants. This occurs when water is leaving the plant faster than it is being taken into the plant. During the Winter months desiccation can occur if the ground is frozen beyond the depth of the root system. If the Fall has been dry, there may not be enough ground moisture available for the plant. Water loss is greatest during windy, sunny conditions. This type of injury appears as discolored or burned evergreen needles or leaves.
After a killing cold some plants may be frozen back to the ground but lower buds and roots often survive. It can take these plants months to begin growth. Give them at least the Spring months to show signs of growth. I had a Clethera that did not regrow until Summer. I had just about given up on it but it showed me how persistent plants can be.
Okay, you have this plant that has lost all its leaves, looks naked and you are figuring it is a goner. Take a look at the bark or stem, is it black, shriveled or separated from the trunk? It’s most likely beyond help if it is. Don’t look just at the top but down at the base.
Next start high and scrape a small section of the bark. If you find brown at all keep moving lower until you find green, believe me you’ll know when you find it.
When you find an area of green, cut off everything above it, on that stem or branch. When you get done going over this you may have a plant that stands a chance of coming back. This really needs to wait until Spring though.
Remember, not only was the foliage, branches and stems exposed to the cold, so were the roots. No matter how hard you try the plant may not survive. The root damage may be so severe that you’ll be fighting an uphill battle.
As much as you may love your plant, you must be realistic, It may be too far gone!
I get teased all the time about my infatuation with what the weather is doing, what it is going to do and what it has done in the past. The best remedy is to keep your eyes on the weather, bring your plants in before the cold hits, and to grow things that are suited for your climate zone.
I hope everybody has a Very Merry Christmas!
Happy Growing!
Darren