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Monday, March 4, 2013

Spur or Cane Prune My Grapes?

Q. Every year my grapes on my Thompson seedless grape vine are small, about the size of a large pea. The taste is wonderful but I would like to get the berries larger. I understand that grape growers use a chemical to make them larger but I would rather not use chemicals if I don’t have to.

A. Getting better berry size on grapes means you have to reduce the number of total berries on the vine. The berries are small because there are too many berries for the size of the plant.

Grape bunches are triangular in shape.  To get larger berries in a bunch,
remove some of the berries from each bunch. This way each berry gets
more of everything from the vine and get larger. To remove berries, you
can pinch the bottom third off of the bunch when the berries are very small..
the size of a BB. This tends to make the bunch round when it is harvested
rather than triangular. Did you ever seed round bunches of grapes in the store?
This is why.
            The first step is to reduce the total number of grape clusters on the vine. Grape clusters are produced on last year’s growth. If you look at your vine, you will see that last year’s growth will be a lighter brown, or sometimes a reddish brown, compared to older growth.

            Once last year’s growth has been identified, then it must be cut back to reduce the total number of bunches the vine has to produce. If the grape is trellised, it is much easier to see where to cut. If the grape is left sprawling, then it is more difficult.

On a trellised vine, we normally want last year’s growth about 12 inches apart. If you haven’t finished your grape pruning, you still have time. You should be finished before you see new leaves emerge.

            There are two ways of pruning grapes; spur pruning and cane pruning. Spurs are created by cutting back last year’s growth so that only one or two buds remain. This means last year’s growth is reduced to an inch or less in length.

This is a grape spur. This spur had two buds. You can see the growth from
the buds. This will produce two or more bunches of grapes. If you are really
daring you can prune to leave only one bud and shorten the spur even more.
This type of pruning, spur pruning, is done to most grapes. However, if you spur prune a Thompson seedless grapevine, it is very possible you may lose most of your fruit. This is because the first ten buds or so on last year’s growth will not produce grape bunches. They are fruitless. In Thompson seedless, spur pruning cuts off buds that produce grape bunches.

Thompson seedless, along with Black Monukka, should be cane pruned, not spur pruned. Canes are just extra-long spurs. Where spurs are pruned so that only an inch or less of new growth remains (one to two buds), canes are pruned long enough so that you have ten to twelve buds remaining on this super long spur.

This “extra long spur” is no longer called a spur anymore. It is now called a “cane” due to its length. Once the grape plant begins to flower in the next couple of weeks, you must then reduce the total number of grape bunches. This is called “balancing the fruit load”. Balancing the fruit load really means reducing the total number of grape berries so that the leaves can produce enough sugar and energy to make the berries that remain, larger.

The number of berries are reduced primarily by two methods; reducing the total number of grape bunches and reducing the size of the bunches. When the berries are very small, the size of a BB, bunches are removed so that the remaining bunches are large and spaced about ten or 12 inches apart.

Rotating Your Vegetables and Vegetable Families

When planting your vegetables you should be rotating your vegetables to different spots to avoid building up nasty diseases and insect populations that can make your job of disease and insect control much more complicated. Rotate back to the same spot in about three to five years. Generally there should be a physical separation between these spots or beds so when you are preparing your soil you are not contaminating it. How important is this concept? It has been around for many many years and is one of the most simple concepts in organic and conventional gardening. Here is something I wrote for an NGO a few years ago when working in Lebanon.

Rotating Vegetable Crops to Prevent Diseases

Rotating fields to different crops each year is one of the most important and easily implemented disease control strategies for farmers. This practice avoids the buildup of many plant diseases in the soil. The longer the rotation before coming back to the crop, the less likely a disease will occur. Because diseases usually attack members of the same plant family, it is best to avoid planting crops after each other that belong to the same family. Insect damage may increase when the same crop is planted in the same area over several years as well. Here are some common vegetables and the families they belong to.

Tomato Family: Tomato, potato, eggplant, peppers
Cucumber Family: Cucumber, melons, squash, pumpkin, gourd
Lettuce Family: Lettuce, endive, salsify, Jerusalem artichoke
Onion Family: Onion, garlic, leek, shallot, chive
Carrot Family: Carrot, parsnip, parsley, celery
Cabbage Family: Cabbage, broccoli, cauliflower, Brussels sprouts, kohlrabi, turnip, radish, Chinese cabbage, kale, collards, rhutabaga
Beet Family: Beet, Swiss chard, spinach
Pea Family: Peas, snap bean, lima bean, soybean
Okra Family: Okra
Corn Family: Sweet corn, field corn, wheat, barley, oats

Some choices of crop rotations include Pea Family to Corn Family, Lettuce Family to Cucumber Family, Cucumber Family to Cabbage Family, and Cucumber Family to Corn Family. Rotating beans with a grain crop such as barley, oats, rye, wheat, or field corn or with a forage crop is very beneficial for root-rot control. One or two years in a grain crop is often long enough to prevent severe root rot when the field is not heavily infested with this disease.

Some diseases that come from the soil are not easily controlled by rotation. Such diseases can live a long time in the soil and are not affected by rotation. Examples include clubroot that attacks the Cucumber Family, Phytophthora blight, and Fusarium wilt of several crops. Other diseases attack so many vegetables that they can survive indefinitely on many different plants including weeds. These diseases include Sclerotinia, Rhizoctonia, Verticillium and root-knot nematodes. Many diseases can survive successfully because they can live on plants and plant parts left in the field after harvest. However they are unable to survive once the plants left in the field decompose. Destruction of plants and parts of plants left in the field after harvest can eliminate this problem. Plowing the field after harvest and before letting the soil rest can reduce the amount of disease that will survive.

Can You Spray a Mesquite Tree and Get Rid of Those Nasty Pods?

Q. I have two large Mesquite trees in my yard and both drop a huge quantities of seed pods annually.  I have heard that Mesquites can be sprayed with the same chemical used on Olive trees to prevent them from setting fruit, does this material work on Mesquite trees?  If so, what is the optimal time of year to spray, what is the name of the spray and can I purchase it at my local nursery?

A. Theoretically you can. The problem is two-fold. Technically the chemical to be used falls under the label requirements for a pesticide even though it really doesn’t kill a pest. Because it is categorized as a pesticide, it falls under the legalities of pesticide use.

If mesquite trees and the purpose of preventing seed pod formation are not on the label, no one can legally recommend it for that use or it violates federal law.

Secondly, to prevent pod formation from the flowers you would need to know the right timing and the right dosage to get results. Neither appear on the label to my knowledge. If someone were to attempt to control the pods, that person would have to "guestimate" what the right concentration would be (how many tbs or teaspoons per gallon for instance) and the right stage in flower and pod formation to make the application.

Some of these chemicals have to be applied only when the flowers are open. Since the flowers don’t all open at the same time, the tree would have to be sprayed multiple times.

Some types of chemicals that cause flower drop, or prevent pod or fruit formation, have to actually land inside the flowers to cause the flower, pod or fruit to abort. Other chemicals can be sprayed before flowering, taken up by the plant and systemically moved around inside the tree where it can cause the flower to abort.

So even if I was legally permitted to tell you to try it, I would not know what concentration to use unless it is stated on the label. The timing of the spray is pretty straight forward. The label would tell you to spray when the flowers are open or at some other time before or during flower development.

You should be aware that some of these products can damage or even kill other plants if this type of spray were to land on them. So theoretically it will probably work if you knew the right dosage and time of application but I am not recommending it.

Invasive Plants Not As Invasive in Desert Landscapes

Q. I have a narrow area and the local Vegas nurseries have Privets (L. Japonicum) which have been espaliered and was thinking that might work well. However, I have read on various blogs that birds eat the berries and they get dropped in other areas of the yard/gardens, sprouting up all over. They say it is considered an invasive species in many areas.

Have you found this problem to be true and if so, is there anything that can be done so that the plant will not produce berries? I was also looking for info on the extent to which I would need to prune the privet, it to keep it to appx a 6x10 espalier (it will go in a back upper planting area making access to it not very easy). If you have an educated guess as to whether this would require 1x year or 10x yr, etc., I would appreciate it.

A. I have not found this to be true in desert landscapes where we can control most growth by where water is applied with drip emitters. There are many invasive species in California and Florida that are not invasive in home landscapes in the desert for this reason. However, invasive species can be a problem in persistent or perennial waterways such as the Colorado River basin, washes like the Las Vegas Wash and irrigation ditches. So you do have to be careful with invasive species but in the middle of the desert with no such waterways it is not usually a problem.

They are not terribly fast growers but I think you could have a pretty nice espalier going in about three to four years. Most of the pruning (if I am picturing what you are trying to do correctly) would probably be done with a hedge shears after the main stems have been established and anchored to the trellis. During the establishment period you would want to push stem growth as quickly as possible with deep irrigations and light fertilizer applications about four times a year. Pruning should be done about monthly during establishment and to keep the trellis looking neat and trim.

Cumquat Offcolor Could Be Many Things

Q. Here is one of two cumquat trees that I am trying to grow.  As you can see it is not working.  I feed and water them what is the problem? Can you help?  Or should I discard. This is one of two that I will send you.

A. The issues on the other picture could be related to a mineral fertilizer problem. This one could be the same but with the leaves gone it is hard to tell. It also might be related to whatever soil amendments you put in the ground when you planted the trees. But I am pretty confident it has to do with the soil, fertilizer issue or irrigation.
Reader's kumquat (cumquat)
It does not help much that they are surrounded by rock mulch. Let’s handle one at a time. Make sure the tree was planted in your soil at the same depth it was in the container. If there was some extreme cold weather, it might also be cold weather damage if you did not see this before it got real cold.

Irrigation. Irrigations should be generous but not frequent. A tree that small can get by with ten gallons of water at each application. If these are on drip emitters you should have enough emitters or run the minutes long enough to deliver ten gallons at this size in its life.
This time of the year once a week is often enough. When you start to see new growth, bump it up to twice a week with the same volume of water each time.

Fertilizer. Go down to Plant World Nursery on Charleston (they are the only nursery I know of in town that carries this) and buy a one pound container of iron chelate fertilizer. If you ask for Doug, Brian or any of the main staff they will direct you to the right one since I recommend it a lot. They even have my name on the label now so people will believe them when they direct them to this product.
Reader's kumquat
For each tree mix about two or three tbsp. in a one gallon container, stir it and distribute it around the base of the tree where the drip emitters are. Water it in with another gallon since it is sensitive to light. Get some rose fertilizer (like Miracle Gro type) and use it on the kumquat or get some fruit tree fertilizer stakes and put the fertilizer under the rocks or drive two stakes close to the emitters. I think the Miracle Gro is better.
Fertilizers are salts. Keep all fertilizers at least 12 inches from the trunk when applied.

Mulch. If this were me, I would pull the rock mulch back a couple of feet and put down some good compost (don’t buy cheap stuff) and lightly dig it around the trees from the trunk to a distance of about two feet from the trunk. I would cover the area around the tree in wood mulch but not bark.
Keep wood mulch six inches away from the trunk so that it does not cause the trunk to rot if it gets wet. Older trees it doesn’t matter.

Let’s see if this works for you.

March is the Time for Planting Onions from Transplants

Plant onions in ammended soils and at the same depth as they were
growing as transplants. You can see where that was on the transplant.
Soil was enhanced with a phosphorus fertilizer.
The middle of March is the time to plant onions and sweet corn. Onions are planted from small plants called transplants. Many onion transplants can be started from seed the previous October or they can be ordered online now from places like Dixondale Farms in Texas. Other places have them as well.


Onion transplants are planted right along side the drip
tubing or drip tape in this case.

I like to use mulch for onions growing in the desert. This is straw mulch.
It helps to conserve water and keep the soil moist. Evenly moist soils is
important for good buld development.
This is Walla Walla and typical of the sizes you will get
if you amend desert soils, keep the soil moist and
sidedress with nitrogen once a month.
Don’t worry about getting short day, long day or intermediate – they all work at our latitude including Vidalia, Walla Walla and Sweet Georgia Browns. Some of my favorites have been Texas Super Sweet and Yellow Granex in the short day category and Big Daddy and Walla Walla in the long day category. One of my all-time favorites is Candy and don’t forget Super Star!

Red candy apple onion. Great onion bud does not develop
the same size as Candy, Contessa, Big Daddy and other yellow/white
Why grow onions when you can buy them in the store? Because they taste SO much, unbelievably better! You can’t go wrong with any of those I recommended PROVIDED you have prepared your soil ahead of time. I like the soil prepared well enough so that you can dig in it with your hands. Not that you have to, it’s just an indicator that the soil was prepared enough.

I Like Raised Beds But You Dont Need Sidewalls

Desert soils with very poor structure and almost zero organic matter
in them need to be "ripped" deeply first. The irrigation drip lines
was used to wet the soil after ripping it. If  you look closely, the
drip lines are on now wetting the trenches to make the soil easier to
rototill after the compost is added.

I like raised bed gardening without sidewalls. In other words, you do not have to put up cinder blocks or build a large coffin to make a raised bed. Raised beds can be formed using the natural slope of the soil at the edges of the bed to retain the integrity of the bed.

Next, these soils need lots and lots of good quality
compost added to the surface of the bed in preparation
for rototilling or mixing with the native soil. The soil
beneath the compost was wetted before the compost
was added.
I posted instructions on “how to build raised beds” on my blog last year. Search the internet for “Xtremehorticulture of the Desert” and use the search window to type “how to build raised beds”.

Many desert soils are notoriously poor for
growing fruit and vegetables. But these same
soils can be made very productive if they are
modified with good quality compost. However
desert soils in the Las Vegas area that have been "modified" take about three years of continuous
cropping and modifying before they will produce some wonderful vegetables. Fruit trees will respond sooner than this. Dont get me wrong... you will get good vegetables the first year after thoroughly composting the soil but to get the highest quality will take you about three. And I mean VERY high quality. These desert soils are FULL of minerals...mostly good and a few can be bad but these bad ones will be mitigated over a couple of seasons of growing.

This soil is mixed thoroughly with the compost as deep as possible. Here we
are ripping the soil again with the compost on top. A rototiller will work
fine for small areas once the soil has been ripped and wetted.

The raised bed is finished. This ten foot (3.3m) wide planting
area was divided in half with an 18 in (0.5m) walkway.
The walkway was created by using a manure shovel
and adding the composted soil to the 3 foot (1m) wide
raised beds. The raised beds are elevated about one foot (0.3m)
above the walkway. Raised beds are seldom walked upon
when finished.
Generally, raised beds are about one yard wide and as long as you like. Walkways between the beds are about half a yard wide. You should have enough spaces for vegetables so you can rotate your vegetables to different spots each year. This helps keep pests and diseases from going rampant in your garden.

The irrigation system you see in these raised beds are made from PVC, some drip fittings, and in-line drip tubing such as Netafim's and Jain's.  I like the one gallon per hour emitters spaced about a foot apart if I am wetting the entire bed. Adjacent drip tubing is connected to the PVC pipe so the in-line emitters are triangularly spaced. If I dont need to wed the entire bed then I use in-line drip tubing the appropriate distance apart.


Can You Use Eucalyptus Wood and Leaves for Mulch or Composting?

Q. Can eucalyptus leaves be used for compost or mulch?
A. The research supports the idea of using eucalyptus leaves, composted or uncomposted, as a mulch or composted as a soil amendment. No problems using it. This is contrary to most public opinion.




How Far Apart Should You Plant Fruit Trees?

Q. I know that the fruit trees at the orchard are spaced closer together than "recommended" spacing.  With the way that they are pruned, it works out really well.  I was wondering if you remember how far apart they are spaced, and how distant the rows are from one another.
UNCE Orchard square spacing of ten feet between trees
and between rows. The trees are about 15 years old and
wood mulch is covering the soil. Trees are watered using
a bubbler and basin that floods an area about six feet
in diameter under the tree. Thre orchard aisles remain dry.

A. The density of trees at The Orchard might be considered "moderately dense". The trees at the Orchard are spaced at ten foot (3.3m) intervals in the rows and ten feet between the rows. If I were to do it again, I would use the ten foot spacing between trees but ten feet between rows is a bit tight if you want to get anything wider than a human torso down the row. Spacings closer than ten feet apart in the rows will probably result in hedgerows where you cannot easily walk around an entire tree in the row.

I would space the rows 12 - 14  feet (4.0 - 4.6m) apart for more convenience.  You can actually space them closer than 10 ft apart in the row but at about an 8 foot spacing you would probably no longer be able to walk around each tree individually and the row would be maintained more like a hedge-row. They are pruned to a height of about six and one half feet tall as well for ease in harvesting, thinning, spraying, etc.

One part of the orchard is on "square" spacing and another is "triangular" spacing. Square spacing is where the trees are directly opposite each other in the rows and between rows. In triangular spacing every other row is offset half the planting distance. This actually gives you a little bit more spacing between trees in adjacent rows; about 13 ft (4.3m) instead of 10 ft. Triangular spacing also reduces shading from adjacent rows if you plant East and West rather than the traditional North and South row orientation in moderately high density orchards.

All of these trees are standard sized fruit trees on "normal" rootstocks, not dwarfing rootstocks with one exception: apples. Apples are on M111 semi dwarfing rootstocks which keep the trees normally at about 80% of their full size. The rest of the "dwarfing" to keep them bearing at this spacing is done through aggressive pruning.

Let me explain further. These trees are pruned aggressively in the winter months (dormant pruning) and also summer pruning which is actually done in mid Spring, around April. Summer pruning is the removal of very aggressive (stems that shoot straight up, called watersprouts) new growth. This can be done by pulling this type of growth out of their place of orgin. At this time of year, they will pop out by pulling very easily.

The older growth is not pruned at this time. That is normally done only in dormancy unless I see something that was missed. Then I might prune it out but that rarely happens.