Wednesday, May 20, 2015
Tuesday, May 19, 2015
This cool weather has caused some unusual plant problems we normally do not see in the hot desert. One reader contacted me to let me know that his tomatoes were not quite the size of a tennis ball, still green and didn’t seem to be growing anymore.
|Tomato growth and fruit ripening slow during cool night temperatures|
Another reader told me his newly planted grapes were not growing. Both readers wanted to know what to do.
The answer to both is to wait. Both of these plants love warm weather. In fact, grapes love the heat. Our nighttime temperatures have been in the 50s and 60s. Most plant growth occurs at night, not during the day. Tomato gets chilling injury at 45° F.
Be patient. It will get hot. Tomatoes will ripen. Grapes will grow an inch every 1 to 2 days when temperatures are above 100° F. All we need are warm night temperatures.
Q. I'm not getting a very big crop of pomegranates this year. They are about 6 years old. We have a large ash tree in the yard which throws some shade but the pomegranates both get morning sun. I heard they don't require much water so I was worried they were getting too much. Then the Homeowners Association switched from grass to desert landscaping this past year.
|Flowering of pomegranates requires the tree to be in full sunlight|
Pomegranates produce flowers on new growth. If you are getting lots of new growth and there is enough sunlight there is no reason you should not be getting lots of flowers at that age. The key will be the number of flowers it's producing. If the tree is not producing flowers of course it can't produce fruit.
To stimulate flower production they need the same amount of water as other fruit trees. This plant is very drought tolerant but it needs water if it is to be productive. The amount of water depends on its size. The frequency of watering is the same regardless of size.
A six-year-old pomegranate should be at least 4 or 5 feet across. Its height depends on how it is pruned. An indicator it is getting plenty of water is the density of the canopy. Your pomegranate tree or bush should be dense enough you would have trouble seeing through it.
If you are not seeing much new growth and the canopy is not dense, this is usually an indication it's not getting enough water. Of course production increases if fertilizers are applied as well.
Surface wood mulches help retain water in the soil and improved growth and production of these plants.
Q. My newly planted grapes aren't really growing fast and are a bit more yellow than dark green. I am wondering if I need to water more. I am only watering two times a week or water less. Or if I need to add something to the soil? Or do nothing and stop worrying?
A. Grapes love the heat. It is probably just not warm enough. Watering twice a week is right when temperatures are beginning to warm.
Apply about five gallons each time you water newly planted grapes. Put a steel stake next to them or a piece of rebar and tie them tightly to it so they are straight. Use the stretchable green nursery tape. Do not use wires.
If you are planning to trellis these grapes, remove all leaves along the trunk except the new growth at the tip. You do not want side shoots to develop along the trunk unless you are growing it in a tree form.
|Grapes grow slowly during cool weather|
The leaf yellowing could be caused by cool nighttime temperatures or a lack of nitrogen fertilizer. Apply nitrogen fertilizer once a month to the soil around the trees and water it in. Do not apply closer than about 12 inches to the plant or you could burn them or worse.
I see from the pictures you sent you have a lot of rock mulch surrounding your fruit trees and vegetables. Our soils have horribly low amounts of organic content, some of the lowest on the planet.
Grapes, all fruit trees and vegetables including strawberries do not like rock mulch at all. This will be a problem in the future. They like “organic” soils, not rock or mineral soils. The small amount of wood chips you have spread a few inches around your plants will not help them at all.
Wood surface mulches need to be at least 3-4 inches deep and a distance of at least three feet from their trunks. Keep wood mulches several inches away from the trunks of young trees and vines.
Q. I live in Sandy Valley and will be building some raised bed planters in my backyard. I have seen gopher mounds all over the property and wondering what is the best way to get rid of them before I start this project. One neighbor says they are so prevalent on the north end of the valley they ignore them altogether.
|Gophers make pretty big holes and you can find fresh soil pushed from the excavation.|
A. Gophers are tough to control. The options are to kill them, exclude them from desirable plants or catch and relocate them. When gophers have other food sources in the neighborhood using repellent plants in your garden might work since your neighbor’s plants will then seem more delectable.
When gophers find a food source, they make more gophers. Your raised beds will encourage them to set up a base camp, living quarters and a dining commons. The bottom line is they are attracted to your water and the soft, juicy succulent plants you are growing.
There are baits and poisons you can use but you’ll have to be very careful not to poison other animals in the process. Your best option is probably to exclude them from your growing area with a wire mesh barrier. You would need to move all your susceptible production into raised beds and place wire mesh at the bottom of the bed before filling it with garden soil.
It is best to read through this for your options. http://cesonoma.ucanr.edu/files/27165.pdf
|Fruit of one variety of jujube|
Q. I just bought a new house with big yard at Summerlin. I am Asian and there are three trees I want to plant most but I don’t have any experience; Jujube, Hachiya persimmon and white saucer peach. I read some of your articles and decide to ask your advice before I take the action.
A. Jujube, or Chinese date, grows extremely well in our climate and you will have a lot of success growing it here.
The biggest problem is its invasiveness. Jujube suckers from its roots in new locations wherever there is water. These can be distances of 5 to 20 feet away from the mother plant. Over time, you could have a forest of jujube from a single plant. Just keep the suckers eliminated when you see them.
Sadly, Hachiya persimmon does not perform as well here as Fuyu and other persimmons. We have trouble getting good fruit retention (fruit staying on the tree) after the fruit has set. Plenty of blossoms but the fruit drops when it gets about ½ inch in diameter and the tree produces only a few fruit. I would suggest trying different varieties of persimmons such as Fuyu, Giant Fuyu, Coffeecake, and others).
The white, flat peaches perform very well here with a very high sugar content and excellent flavor. I would suggest donut peaches such as “Stark Saturn” or “Sweet Bagel” varieties. These peaches may also be called saucer or peento peach.
If you keep your trees healthy by planting with plenty of compost mixed in the soil at planting time and covering the soil surface with wood mulch you will have fewer problems. You can always email me with specific questions.
Q. We are small farmers owning 2 acres of land in India, We have just seen your opinion on RO water for horticulture crops. We are growing roses and colour capsicum under poly greenhouse cultivation. Our ground water electrical conductivity level (salinity) is too bad that it comes to 1.8. So our plants came to death condition. We heard about reverse osmosis system and fixed it to our farm. By this system leaves shrinkage and nutrient deficiency had risen. So we are pleasing to suggest your idea about it. We are looking for your grateful suggestion.
A. Pepper plants are very tolerant of this level of salinity. It only becomes a problem if we let the soil becomes excessively dry or if the drainage of the soil is very poor and the water drains slowly. Improve the drainage of the soil and irrigate so that the soil never dries to less than 60% of its water content. With a little bit of experience, you can determine this just using your hands and feeling the moisture content by squeezing it and using your fingers.
The kind of salts that you have in the soil will dictate if you were to use soil additives such as gypsum or not to help flush the salts from the soil. Sending a soil sample to a soils laboratory to determine which salts are present would be very helpful.
Generally speaking we start to see yield reduction in pepper at about 1.5 dS/m (mmhos/cm). You are close to that threshold at 1.8. I think you would only need to dilute your irrigation water maybe 20% with RO water to get below this threshold.
New Mexico's advice on salt damage to peppers
Another option is to water with your irrigation water and then flush salts using an irrigation cycle using water with lower salts. Use these in an irrigation cycle of salts/low salts/salts/low salts/etc.
Monitor your drainage water for salt content. Monitoring your drainage water and recording it regularly will help you with managing salts (flushing, etc.)
Two types of salt damage occurs to plants; one is due to total salts (EC) and the other is due to the type of salts (specific ion effect). Particularly damaging are sodium, chloride and boron. If these salts are involved then this might mean a very different problem than just salts in general.
What to do?
- If it is possible, determine which salts are present and not just the level of salinity (1.8).
- When irrigating never let the soil or substrate dry out too much.
- With high salts you should be irrigating frequently with a smaller volume of water. This prevents the salts from becoming too concentrated.
- If you can over irrigate and flush salts from your soils make sure you over irrigate by about 20% to keep salts moving through your soil profile and maintain a steady state of salts and prevent the buildup of salts.
Depending on the type of salts in your irrigation water you will see different nutrient deficiencies.
Note: This question was from farmers in India. Potable water, water in the Las Vegas Valley coming from the tap, is close to this level of salinity or salts. This is because a large percentage of this water comes from the Colorado River unless you are on well water. Salt levels of our native soils here in the Las Vegas Valley are 25 times this level. Water management is very important to control salinity.
Posted by Xtremehort at 12:24 PM
Labels: increasing yield of pepper because of salts, salinity damage to pepper how to correct salt damage, Salt damage to peppers
Q. I dug up some standard sized oleanders from my neighbor’s yard. They were healthy for years and some were 8 to 9 feet tall. I transplanted them about six weeks ago and used transplanting fluid every 6 to 7 days. I also watered them every few days. The leaves are all dry and crinkled so I pull them off. They are dead now and just look like sticks. But I see new growth coming from the base. My husband tells me to pull them out and buy some new ones. Will these make it?
A. When you dig up plants that are this old you can only get about 10% of their root system. With a
|Oleander will sucker from the base if it is cut back. When relocating an older Oleander you should cut them back to make up for the lost roots.|
If you want to keep them, it is best to just cut them off with a few inches above the ground and let them regrow from the base. Just keep the soil around the roots watering about once a week now and twice a week when it gets really hot.
They will survive and I would be surprised if anything grows from the stems that are taller. The transplanting fluid was not necessary. They would've done what they're doing right now with or without it.
In the future when you move plants that have been in the ground for more than two or three years the success rate is pretty low unless you have a history of doing it successfully.
Q. Our flowering plums have been infected by what was diagnosed as “sooty canker” disease.
|Sooty canker on Apple|
They were treated by arborists but the blight continues. Infected limbs were cut until one of the trees needed to be removed entirely. I am advised this blight has become epidemic in Las Vegas Valley. Is there a solution to cure or at least treatment for sooty canker?
A. Be careful on any diagnosis of sooty canker. There are a lot of natural things that can look like it and if you've never seen it before or don't have much experience around it, it can be easily misdiagnosed.
|Sooty canker on poplar|
Sooty canker disease causes limb dieback and the bark of the dead limb to peel away revealing a black, sooty powder on the wood. When you take your finger and rub against this black powder it will come off on your finger and look just like soot from inside your chimney.
There are other natural black “powders” on limbs which will also rub off on your finger. But sooty canker is jet black on your finger and unmistakable once you see it. I will post a picture of sooty canker on my finger on my blog so you can see what I’m talking about.
|Beginning of sooty canker on Mulberry|
I disagree, it is not an epidemic in Las Vegas. It attacks a small number of trees every year at about the same rate for the past 30 years. Many trees can become infected but we see it most frequently on Mulberry and Poplar (cottonwood) and occasionally on Ash and Elm.
I don’t remember seeing it on truly desert trees such as Mesquite, Acacia or Palo Verde.
It can be spread easily on pruning equipment if the equipment is not disinfected between cuts and between trees.
Be very careful when this is diagnosed. If a limb is dead, it is dead and must be removed. We don't want to be removing limbs with the wrong diagnosis.