Considering the top viewed blog post this month is how to protect fruit trees from freezing temperatures, I thought readers would be interested in how we are protecting our hardy kiwi vines from a late spring frost.
Arctic kiwi are hardy to -25F once fully established, which is roughly zone 4. However, while the plants are young, they are very tender and can easily be set back a year by a late spring frost. I am sure if you have a kiwi, and have done any amount of internet research, you know that many people complain that their kiwi vines never produce fruit or the growth is usually nipped by late spring frosts. Having to recover from this set back can cause the plant to expend stored energy on new leaf development, instead of producing flowers.
To help understand why you need protection, here is a bit of science: In the summer, a plant produces energy by photosynthesis. This energy is necessary for life; just like a grizzly bear, the plant eats and grows fat all year long, and then sleeps through winter. Humor me for a moment, and imagine each leaf is a solar panel, and that under the ground beneath the plant is a battery, just like the one in your car. All year long the plant is charging this "battery", so that when it shuts off in late fall, the battery is fully charged. In the spring, the plant pulls the power from the battery in order to "jump start" the growing season and make new leaves. If you try continuously to start your car in the cold, and it never actually starts running, your battery will drain and "die". Perennial plants are just like your car; they can only try to start for so long before they run out of energy and die. Hardy kiwis are especially susceptible because the leaves are very tender and sensitive to frosts. While they won't normally die from a single late frost, it does set the plant back considerably. It can actually require so much energy to produce a new flush of leaves that the plant has no energy left for vigorous growth, flower production, or fruit, and ends up spending the year looking pitiful, just trying to survive.
If properly cared for, an arctic kiwi should begin producing fruit in the second or third years after planting (Click here for more info). Our vines were planted in Spring of 2013 (1 gallon plants), and are entering their second year. After the near record high temperatures of last week, most of our plants opened their leaf buds and have begun their spring growth. Two days of freezing temps were forecast, and upon waking this morning, I found this:
Yesterday I took the opportunity to put a few protective measures in place. Looking at the forecast, I am happy to have expended the thirty minutes it took to completely protect my plants. The low for today is expected to be around 24 degrees, and then in typical spring fashion, no more freezing temps in the 10 day forecast. I am about 90% certain this will be the last frost/freeze we will have until fall.
The first step in protection is making sure your kiwi is properly pruned. You should have a single "trunk" that runs to the top of your trellis, where it should be cut. From here, 2 lateral branches will be trained out in each direction. If you don't have a good pruning resource, find one. If you look at the kiwi above, before being pruned, you can see it has a mass of "stems" instead of one big "trunk". To prune for the first year, I picked the strongest and most vigorous branch to become the trunk; all others were cut off at ground level. It was then tied to the support.
Remember the battery example I made earlier? Well, in this case, the battery has been charged with enough energy to support the huge bush in the non-pruned example above. Once you remove most of the growth as in the pruned photo, the plant has a lot of extra energy left over. This will cause an explosion of growth this spring, and is known in plant lingo as an "invigorating" prune. This is also effective with really old plants that need a little rejuvenation.
Step 1: Wrap vine with lights. I use the big C9 clear Christmas lights. These are great for everything from holiday decorating, as well as lighting for outdoor dinners, and plant protection! I used one strand per vine and tried to keep the bulbs from touching the plant; if you have lights with clips built on, this is an easy task.
Step 2 (Optional): In order to test the effectiveness of my efforts, I tied a temperature sensor which connects wirelessly to an indoor receiver. After all, what good is an experiment without data?
Step 3: Wrap the entire plant in plastic and secure. I used left over bailing twine from last years hay season. Try to make all of your edges overlap, and don't worry too much about the bottom. Just get it as close as possible to the soil.
Step 4: Wrap in burlap and secure. If you don't have burlap use any old bed sheet, blanket, canvas, painters drop cloth...whatever you may have, it isn't really that important as long as it insulates. By having 2 independent layers the first will hold the heat, and the second will provide insulation from the cold.
I finished it off by piling up a layer of straw around the base. It took one flake to do both vines. The total time from start to finish was 30 minutes, of which most of the time was spent rounding up the materials.
While the real test will be tonight when the low dips down to 24F, last night was a pretty good indicator of the insulation provided. The lights were turned on at 9pm last night, and the low was 34F. As you can see from the thermometer the temperature surrounding the vine (remember that sensor I tied to the post...), dropped down to a low of 48 and had a high of 68 degrees. This corresponds to average daily highs and lows before this wild storm blew through.
In 2 days time, the temp will return to normal, and I will remove all of the protection so that the leaves can get some sunlight and continue their precocious growth.
For the time involved, this project really payed off. I'll post an update at the end of the week with my results as well as a nice post for our CSA members on the status of the gardens. Hopefully this helps a few of you get those elusive kiwi fruits you have been after!
What a lovely week it has been on the farm. A long list of chores were finally accomplished, and we managed to have perfect weather for planting the spring garden. Onions, beets, Swiss Chard, collards, kale, mustard greens, pak choi, spinach, fennel, parsley, dill, cilantro, carrots, lettuce (leaf, romaine, and iceberg), arugula, peas, cabbage, and broccoli were all planted. While we will not be able to harvest from them this year, we are also adding 250 asparagus plants, and 250 strawberry plants to our perennial beds. We will begin harvesting from these in 2015.
Now that we have finished planting the majority of the spring garden, we can finally predict the start of the CSA program.
Members can expect the CSA program to begin on either May 16th or 23rd.
Cabbages were carefully transplanted just before an afternoon shower began. By timing our transplants to be just before cloudy, rainy weather we can push the odds much more in our favor. Transplanting is very hard on plants, especially cabbages. They tend to readily wilt, and they are much more sensitive to their planting depth and handling. Because of this, we hand plant all of our brassicas. It ends up taking us about 30 min for a 250' row, which will hold about 100 cabbage plants. Compare that to planting tomatoes, which is done with a transplanter pulled behind the tractor. It takes us about 3 minutes to plant a 250' row.
Thankfully, most of the spring garden is planted by seed, and that is easy work thanks to our Jang precision seeder. It can separate the tiniest seed so that there is no overplanting, and thus no wasted seed. After selecting the correct spacing, and seed wheel (for seed pickup), you load the seed, set the depth, and begin pushing. It takes about 2 minutes to plant a 250' row, which includes opening the ground, setting the seed, and covering the seed with the proper amount of soil.
A panorama of both of our gardens on April 1 2014, which total about 1.75 acres in size.
The first crops to be ready will be lettuce, arugula, radishes, baby carrots, bunching onions, petit beets, Swiss chard, spinach, dwarf pak choi, mustard greens, parsley, and dill. The next big addition of variety will happen around June 1st (~week 3 of CSA program). It will add the following to the existing availability: rapini, sugar snap peas, garden peas, and red cabbage. In mid June (~week 5/6 of CSA program) life is good: Romaine lettuce, green cabbage, fennel, cilantro, broccoli, new potatoes, green beans, cucumbers, collards, summer squash, zucchini, scallop squash, and kale. Around July 1st, most of the summer garden will be producing, and the spring crops will slowly be retired. Don't worry though, most of them come back for a repeat appearance in the fall!
Members, I hope finally knowing the starting date will help ease your anticipation of the first harvest. If you are taking the challenge of eating seasonally, now is the time to look up recipes and preservation techniques for all of the produce you will be getting. I cant say it enough: You can never have enough recipes for summer squash & zucchini! Take the time to google different cooking techniques. Thai, Indian, Chinese, and mediterranean styles of cooking tend to be more vegetable heavy, and have much more variety of uses for each vegetable type. For example, you aren't going to find very many American dishes for eggplant, but there are hundreds of asian dishes that feature it. These styles of cooking are also generally more healthy than many others. Of course, I will feature many of my favorite (and not so healthy) southern recipes throughout the year: Fried green tomatoes, green beans with new potatoes, fried corn, and many others. I will also be sharing step by step guides on preserving some of the more plentiful items we offer. We will cover everything from making dill pickles, pickled pepperoncinis, chili powder, sun dried tomatoes, and much more.
Until next week...