This episode discusses how to get Bosc pears to produce more fruit when a pollenizer tree is not close by. Bob Morris also talks about knowing when to irrigate fruit trees using the “old farmer technique” and as well as using new technology like soil moisture sensors and a piece of rebar. Everybody knows that water softeners are the bane of landscape plants if you’re not careful. Learn some techniques that might save some landscape plants from dreadful water “softenitis”. Lastly, lemon bottlebrush sometimes has yellow leaves and it’s not because it’s a lemon bottlebrush. Learn how to correct this problem and what causes it. All this on Desert Horticulture.

Personally, I am beginning to question the value of organic production whether it is done in the United States, Europe, Canada, Australia or the Far East. In years past, when organic production was first starting out, I thought it was a great idea and a chance for the small farmer, particularly the local one, to compete in the food marketplace.  I started having my doubts perhaps starting about 5 – 7 years ago for a variety of reasons. However, I still consider myself an advocate for locally produced food and getting to know your farmer as well as Good Agricultural Practices (GAPs), beginning with Eurepgap and more recently Globalgap. Good agricultural Practices focus on a holistic, and in my opinion, a more rational approach toward producing food by small farms. But still, large scale conventional farming will never replace the “local producer”.  I hope you enjoy reading this article from Chemistry World. Read the article here.

Join Bob Morris on his podcast talking about why you should or should not use a fertilizer injector, the difference between a potting soil and garden soil and why Santa Rosa plum might be a good fruit tree to have.

Q. My lemon is not a Meyers lemon but the tree is starting to flower. I didn’t want to pick them this early because they are still getting sweeter. Does the “remove lemons before the tree flowers” rule apply to this variety as well? A. Yes it does. It applies to all fruit trees. Try thinking like a lemon tree. The reason the tree produces fruit is to reproduce. When the fruit drops to the ground, the fruit rots and releases nutrients that feed developing seedlings. Eureka lemon growing in Las Vegas             The tree “knows” if there is fruit attached to its branches or not. It can’t see anything but there are other types of communication that trees have perfected. When the fruit has been picked, the tree “knows” the fruit is no longer there.             The reason for picking fruit before the tree begins flowering is to send “signals” back to the tree that it no longer has fruit attached to its branches. When fruit is missing, the reproductive or flowering cycle of the tree is encouraged.             The beginning of flowering is the beginning of the reproductive cycle. The normal flowering cycle of trees is at certain times of the year. If this time for the normal flowering cycle to begin has passed or is delayed, the tree may not flower at all or flower very lightly.             You are right. Most citrus are considered non-climacteric, or, in other words the fruit doesn’t increase in sweetness after it is picked. It is best to wait when picking lemons to improve its sweetness, but you don’t want to leave it on the tree long enough to interfere with flowering.             Other fruit which don’t ripen or ripen little after picking include figs, grapes, pomegranates, cherries and apples. As a consumer this means the sweetness of non-climacteric fruit does not increase much, if at all, after picking.            If citrus is left too long on the tree fruit quality is reduced because it becomes “pithy”; it starts drying out. Remove all fruit from trees before they begin their next flowering cycle.

Q. I found a Myers lemon at a store in California that looked much different than my Myers lemon; they were smaller, darker orange and seemed sweeter to me. Is this Myers lemon different from mine?  A. There are differences between fruit grown in one geographic location versus another geographic location. Sometimes we call these location differences “agroclimatic regions”. Both were labeled as Myers Lemon. The one on the right was bought in the store.             Agroclimatic regions include differences in weather but also differences in soils. All these “differences” evoke changes in fruit quality, reflected in the quality attributes of the fruit. How the plant is managed or manipulated also creates changes in fruit quality.             We see these agroclimatic differences in vegetables and ornamental plants as well. Sometimes these differences are good and sometimes they are not. We don’t know until we grow these plants in different locations.             Fruit grown in the Mojave Desert does not have the same quality attributes as fruit grown in non-desert areas. There are many reasons for differences in ‘sweetness’, color and sugar content in fruit.             Sweetness or sugar content can be masked by the amount of acidity the fruit has. Fruit grown in the desert typically has high sugar content and lower acidity, so some desert grown fruit may taste bland compared to fruit grown in non-desert climates. Other fruit might be better.             Differences in fruit quality can be attributed to plant differences, agroclimatic regions, how the fruit is managed on the tree or after it is picked. Differences in fruit quality can be from the variety or plant selection, graftage, fruit maturity, climate and weather, plant nutrition, age of the tree, how much fruit is grown on the tree, and others.             Try fertilizing the trees with a good “citrus” fertilizer or compost. Change the amount of water the tree gets and try harvesting the fruit later or earlier. Minimize the length of time the fruit is kept in storage once it is picked and off the tree. Prolonged storage can reduce sugar content.

Q. We have a vegetable garden and an ornamental garden.  We didn’t think about it, but we just installed a water softener.  This softened water also comes out of the garden hoses.  Is this water bad for our plants? A. Yes it will be a problem if you water with sodium-based salts from the water softener in it. Sodium is toxic to plants. This inexpensive salt used in water softeners also contains chlorine which is also toxic to plants. A double whammy.             You have three options. The first is to run a new water line and hose bib from a point upstream of the water softener and use this water for irrigating. Secondly, install a hose bib from the irrigation line used for the garden since the water supply for outside irrigation is connected before the water softener.             The third option is to use potassium-based water softening salts rather than sodium-based salts. These water softener salts are more expensive but less damaging and will still soften the water. You’ll find this type of salt for water softeners anywhere that sells water softener salt.

Q.  How often do deciduous fruit trees, in this case a Blenheim apricot, need to be watered during the dormant season? A. It’s hard to give a blanket recommendation about how often to water because of the differences in soil, root growth and if people are using a surface mulch or not. Because of these differences, how often to irrigate might vary a couple of days either way.             The best way is to use a moisture sensor such as those inexpensive houseplant moisture sensors. Insert the tip in the soil about 6 inches deep and irrigate when the meter is around 6. You should be at able to water no sooner than every 7 days and maybe every 10 days depending upon your conditions. Soil moisture sensor with 24 inch stem             But if the tree is surrounded by dry soil it may be closer to 7 days. If the tree is surrounded by other trees that are irrigated, it might be 10 days. And if you have the soil covered in 3 or 4 inches of woodchips you can extend it perhaps an extra 2 days. That’s my best guess.             But you are better off using a moisture sensor to get it more accurate than this. To determine the number of minutes to irrigate, I use a long probe like three-eighths inch rebar and push it into the soil after an irrigation. It’s hard to push it deeper if the soil is dry beneath where you water. Recently at one of my classes, someone mentioned they are using a wooden dowel to do the same thing. Soil moisture sensor meter reading “0” or dry.             I just push it down until it’s hard to push any further and that tells me how deeply I’ve irrigated. With fruit trees I like to irrigate 12 to 18 inches deep. 

Q. I planted a Bosc pear tree seven years ago not realizing it required a second pollenizer pear tree.  For several years I did get a few pears even though the tree had lots of flowers. I think my neighbor’ s pear tree was the pollenizer, but it seems to be failing. I have no room to plant a pollenizer pear tree. Not sure what to do.   A. I have grown Bosc, Anjou and Bartlett here in the Mojave Desert in the past and noticed, the same as you, the fruit set wasn’t great in the Bosc and Anjou compared to the Bartlett. It is possible it might be a humidity problem, like our problems with sweet cherry and Hachiya persimmon growing and setting fruit in our climate. Bosc pear producing immature fruit in the Las Vegas valley             Bartlett and Red Bartlett seem to set fruit better in the desert, compared to Bosc and Anjou when there is plenty of flowers and honeybee activity. Keep that in the back of your mind. Bartlett pears produced in the Las Vegas valley.             Since Bosc needs a pollenizer tree, you will have problems producing  fruit if there is no other European Pear flowering at that time. It might be possible to buy a Bartlett and plant it on the south side of that tree, 18 inches away, and prune out some limbs to make room for it. In other words, integrate another pear that flowers at the same time and see if that helps with the fruit set of your Bosc pear. Bartlett is a good pollenizer for Bosc. Sensation Red Bartlett producing fruit in the Las Vegas valley.             Make sure you have rosemary or other winter blooming herbs to attract honeybees to the backyard that time of year. Anything that blooms during the spring months and attracts bees will work. Because pear blooms a little bit later than some other fruit trees, you might also consider attracting leaf cutter bees as pollinators to your yard. Comice pear fruit in the Las Vegas valley.             Try putting a small birdbath or shallow water source and that will attract honeybees as well. When it’s warm, honeybees Hall water back to their colony. Put rocks in the birdbath so that honeybees have a place to land and retrieve water. Nesting blocks for leafcutter bees             If you can synchronize the blooming of these two pear trees, and you still don’t get fruit set on the Bosc pear, you can assume it’s a humidity issue. If it still doesn’t set fruit, get rid of the Bosc and at least you can have a Bartlett. I would look closely at Red Bartlett if you want the red color but both Bartlett varieties work here.

Q. Nutrients and fertilizers needed by plants are confusing to me. We have people selling “rock dust” to handle some of these nutrients when they are missing from the soil. How do you know which nutrients are important to plants and how much to apply? A. There are only 16 or 17 “essential” nutrients absolutely required by plants. Some of them are needed in large amounts and some in very small amounts. These 16 or 17 essential nutrients have been placed into two categories; “major nutrients” (needed by plants in large amounts) and “minor nutrients” (needed by plants in smaller amounts). Conventional Fertilizers Fertilizers used by many farmers beginning mostly after World War II, sometimes called chemical fertilizers, contain only three or four of the “major nutrients” needed by plants. The application of chemical fertilizers contributed to the “green revolution” in the late 1950s through the ’60s. These nutrients included nitrogen, phosphorus, potassium and sulfur. When used correctly, these fertilizers produced miraculous increases in food production. Problems arose when farmers began relying only on chemical fertilizers and neglecting the organics in the soil. This heavy reliance only on “chemical fertilizers” resulted in soils that were depleted of nutrients and “worn out”. Soil Testing Common practices before adding fertilizers included testing the soil for nutrients (soil tests) and testing the plant for nutrients (tissue analysis). These tests determine which fertilizers to apply and how much of each is needed. Soil tests and tissue analysis were common, cost effective practices for large scale producers but costly for the home gardener. The problem was that soil tests, at least for homeowners, were expensive. Nitrogen For small-scale producers and home gardeners, scientific knowledge, gardening experience and observation are used to determine which fertilizer to apply and how much. For instance, nitrogen causes growth of leaves and stems and a dark green color. When this type of growth is slow or needed, nitrogen might be added. When to add nitrogen? Looking at the plant and how well it grows and how dark green was is a good indicator whether nitrogen needs to be added or not. Because nitrogen easily washes through the soil or can escape as a gas into the atmosphere (think ammonia), nitrogen is usually the one ingredient in short supply. Always. So nitrogen can be applied in small amounts, every couple months, on a regular basis through the growing season. Phosphorus Phosphorus is responsible for rooting, improved flowering and fruiting and for a good oil content in nuts and grains. When these results are needed, phosphorus might be added. Unlike nitrogen, you can get into trouble by adding phosphorus too often. When is phosphorus needed? Think of what it promotes; roots, flowers and fruit, and oil. So apply it when new plants go into the ground for their root development. Apply it just before plants develop flowers and fruit. And nuts develop with their high oil content. When other nutrients are seen to be lacking because of how the plant is growing, these are added to the soil or sprayed on leaves to correct these problems. This is not a cost-effective approach for large-scale farmers however. Potassium Potassium is forgotten about a lot by people because it does so much but what it does is not seen easily. Potassium deficiency is difficult to see. We do know that potassium is similar to nitrogen in some ways since it moves through the soil fairly easily and doesn’t stick around like phosphorus does. We also know that potassium does not cause the same kinds of problems as phosphorus if it’s over applied. We think that potassium is needed in about the same amounts as nitrogen by most plants.Apply potassium whenever you can. When to add potassium? Not as often as nitrogen and more often than phosphorus. Using Compost The nutrient content, or fertilizer content, of compost depends on what was used to make it. But in a general way, most compost is pretty rich in plant nutrients. Compost usually is fairly high in nitrogen and phosphorus. It could be a little deficient in potassium. But there is a lot of variation in the nutrients it contains in compost.Applying the correct amount of compost and mixing it into a soil can add most of the required nutrients in their proper amounts with the exception possibly of nitrogen. Nitrogen might be added to some plants to increase growth and improve its production. Rock Dust Rock dust doesn’t have a fertilizer analysis listed on the bag like a bag of fertilizer does. It’s seldom listed on a bag of compost either but that’s because compost can be extremely variable in its nutrient content. Fertilizer laws are very strict in each state. 1 a bag of fertilizers says it has something in it, it better have it or the states weights and measures police could cause some problems. Rock dust is supposed to add plant nutrients back to the soil. This is where it can become a little bit like black magic. We know there are 16 or 17 essential nutritional elements for plants but rock dust claims a lot more than that. In some ways, it has been very fashionable to add rock dust to your garden soil and many people smile and give that addition a thumbs up.

Q. I love my lemon bottle brush shrubs, but the leaves started yellowing. l recently added five inches of organic top soil. Additionally, l think l should add acid. What kind of supplement should l use for a long-term solution? This bottlebrush is yellowing because it surrounded by rock mulch and planted in native, desert soil. A. Leaf yellowing can be caused by many different things. With bottlebrush, it is frequently a shortage of available iron to new growth. More importantly, the soil is collapsing resulting in poor drainage and not enough air reaching the roots.             I see this often when any bottlebrush is surrounded by rock mulch. Over time, the soil around the roots becomes mineralized. In my opinion, all bottlebrush plants, in general, should not be surrounded with rock covering the soil. This is an example of an iron fertilizer that dissolves in water that can be sprayed on plants with yellow leaves.             Once leaf yellowing due to a shortage of available iron, it cannot be reversed quickly by adding soil amendments. The most immediate color leaf reversal would be spraying the leaves multiple times, a few days apart, with an iron solution. But the yellowing will return to new growth as the iron runs out.             Adding an iron fertilizer to the soil, such as an iron chelate, lasts longer, up to about 1 year. It is added in early spring, about now. But the next year you need to add more iron chelate to the soil, before new growth begins. This is also an iron fertilizer but the iron is added as the chelate with the acronym or nickname EDDHA. This particular chelate holds on to iron regardless of the alkalinity or pH of the soil. This is not true of other iron chelates.             But when iron is added to the soil, the leaves which are yellow remain yellow. Green leaf color only occurs in new growth which hides the yellow leaves until they drop off. To turn yellow leaves green again requires a spraying the plant with the iron solution I mentioned earlier.             For the long-term, you must improve the soil where the plant is growing so that the alkalinity of the soil is reduced, and the roots have better access to air. This can be done by adding compost to a soil that has become mineralized and covering the soil with wood chips rather than rock. This is a compost made from municipal solid waste. The compost is made from waste products from the city and includes human waste or biosolids that has been composted. All compost from municipal solid waste must meet EPA’s health requirements before it can be sold to the public.             When preparing a spray solution that contains iron, follow the label directions. But I suggest using either distilled or reverse osmosis water rather than tap water. This is because of the alkalinity in our tap water. In distilled or RO (reverse osmosis) water this alkalinity is removed. I am concerned that the alkalinity in tapwater might interfere with the effectiveness of your iron sprays.             I would also include something to make the spray solution “wetter”. In a pinch you can use a liquid dishwashing detergent but it’s not ideal since it contains so many additives such as hand lotions and perfumes. It’s better to use a liquid detergent which is purer such as Dr. Bonners or a detergent made from Castile soap. This is a liquid detergent, aka surfactant, that I use and purchase online. Notice that it is unscented and it is also certified as organic through Oregon Tilth. This is another surfactant that I like which is made out of saponins or agave extract that can assist fertilizers dissolved in water to move inside the leaf through the surface.             Both the purified water and liquid detergent is important because it helps move the iron contained in the solution through the leaf surface and inside the leaf .             Spray the leaves long enough so that the spray solution begins running off its surface. Spray both the upper and lower surfaces of leaves so that the sprayer is taken inside the plant more effectively.