I am on assignment in northern Afghanistan now, but my readers will still be able to follow the answers to my gardening questions here in the newspaper as well as on my blog. So keep the questions coming!
Q: I don’t know how old my peach tree is. I assume it’s really young, like 2 or 3 years old, because it is small. I am pinching off the small peach fruits leaving one small fruit every 4-6 inches along the branch. For this tree, that ends up being one to two peaches per branch, giving me overall maybe 10 peaches on this young tree.
A: Your thinning of the fruit sounds about right for the age of your tree. Some people pull all of the fruit off of a young tree hoping to get the tree into greater production beginning in its fourth year of growth.
It doesn’t really matter.
I like to have a few fruit from young trees, an incentive for my labor. It won’t hurt the tree to have it produce fruit early.
If your tree is really healthy and puts on a lot of new growth this and the following year, then you should increase fruit production 300 to 400 percent during the next two years.
You should be nearing full production by the fourth or fifth year if you are watering, fertilizing and pruning adequately.
You will prune your tree in December or January. Look for my pruning videos on YouTube under the name Extremehort. This should help a lot.
Q: First off, I want to thank you for the inspiration and motivation to get my backyard orchard project off the ground. I planted 22 bareroot fruit trees this winter, 20 of which have budded out. I am still hopeful on the remaining two.
I also have installed a gray water drip irrigation system using the water from my laundry. The system I am using waters the whole 20-by-30-foot orchard area rather than each individual tree.
What I am curious about now is if I should utilize the surge tank in my system to apply any fertilizers or possibly something to combat the alkalinity of our native soil? I am noticing chlorosis (yellowing) already on the new trees this spring. Do I need to worry about that now?
A: Congratulations on your mini orchard. Be careful with the type of laundry detergent that you are using in combination with your gray water system. Make sure it is biodegradable and plant friendly.
You might want to do some checking on the state regulations on the use of gray water for irrigation. This would be overseen by the Nevada Department of Environmental Protection, and much of that information should be online or a quick phone call away.
Using a fertilizer injection system is very convenient and adequate as long as your irrigation system is designed and installed well. If your irrigation system applies water evenly, then the fertilizer will be applied evenly as well. Make sure you incorporate a 150-mesh screen filter somewhere at the front of the system.
The advantage of fertilizer injection systems are that they can apply small amounts of fertilizer continuously through the growing season . It sounds like a fertilizer injector would apply more fertilizer than applying fertilizer by hand once in the spring, but this is not necessarily so.
Applying small amounts of fertilizer on a regular basis is much more efficient and can lead to significantly less fertilizer applied if you manage the irrigation system and very small amounts of fertilizer closely.
You do not need to inject anything to combat alkalinity of the soil. Select acid-forming fertilizers and use organic mulches. If you use organic mulch on the soil surface, it will do a lot to improve the soil and combat alkalinity.
You could inject an iron chelate into your irrigation system to combat yellowing from chlorosis, provided the water is below a pH of 7.5. If you cannot guarantee this pH in your water, then use the iron chelate EDDHA, which is stable through the alkaline pH range. The other sources of iron fertilizers are not stable under alkaline conditions and will drop their iron once they are put into water with a high pH.
If you decide to inject fertilizers into your irrigation system, then start the injection cycle after the water has been delivered to the plants for a few minutes. Water is not delivered evenly during the first few minutes of the drip irrigation cycle. Once the drip system is fully pressurized, well-designed drip systems apply water evenly.
Stop injecting fertilizer several minutes before the irrigation system shuts down. Several minutes of uninjected water will clean out the irrigation system of fertilizer that might be stuck in the irrigation lines.
Water containing fertilizer that remains in your irrigation system will lead to the growth of algae and bacteria . Algae and bacteria are major culprits in plugging your irrigation system if you are using drip or even sprinklers.
Q: This year I noticed branches growing from the base of my orange tree and the branches have sharp thorns on them. Should they be pruned from the tree?
A: The branches growing from the base of your tree probably are shoots rising from the rootstock; their common name are suckers. Let’s use your orange tree as an example, but it could be other citrus as well such as limes, grapefruit, lemon, etc.
Most citrus valued for their fruit are grafted to another citrus valued for its roots. This citrus valued for its roots is called the rootstock. The citrus plants used for rootstocks are selected for various characteristics but not for the quality of the fruit they produce. In fact, fruit from rootstocks is nearly always pretty terrible.
The rootstock may sometimes be more vigorous than the orange tree itself. The rootstock can send up shoots that, if not removed, may dwarf and overtake the orange part of the tree. Simply remove these undesirable suckers any time they appear and as close to the trunk as possible.
They may sucker from the roots as well. Remove these, too, by cutting the sucker and the root with a sharp shovel and pull them from the soil. This eliminates the possibility that the rootstock will overtake the orange tree.
Do not leave any stubs. These will easily regrow.
Frequently, in our climate, tender citrus like some oranges, limes and others are killed during winter freezes. But, because the rootstock part of the tree may be more cold tolerant, it survives, then suckers and takes over.
In a couple of years the rootstock is the only plant left and the owner wonders why the fruit is terrible and not anything like the citrus fruit he was expecting.
Bob Morris is a horticulture expert living in Las Vegas; he is on special assignment in the Balkh Province, Afghanistan, for the University of California, Davis. Visit his blog at xtremehorticulture.blogspot.com.