Which Fertilizer to Apply and Why

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.

Make Yellow Leaves on Bottlebrush Green Again

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.

Fertilizer and Water Improves Nut Yield in Stone Pines

Mineral fertilization and irrigation effects on fruiting and growth in stone pine (Pinus pinea L.) crop

V. Loewe
A. Alvarez
M. Balzarini
C. Delard
R. Navarro-Cerrillo3

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What is already known on this subject?

This is the first study on fertilization and irrigation in an adult intensive P. pinea plantation, providing a first management proposal for the species.

What are the new findings?

Fertilization enhanced fruit production (›82.3%) and vegetative growth while irrigation enhanced only fruiting. Best fruit production was recorded in fertilized and irrigated plots (›60%).

What is the expected impact on horticulture?

Pine nuts can be produced in orchards applying horticulture techniques as in other fruit crops, improving production quality and quantity, overcoming the traditional view as a non-timber forest product (NTFP).

Summary

Introduction  - Stone pine (Pinus pinea L.) is a species of economic interest for its pine nuts. Despite this market, cones are harvested mostly from natural forests. Advances in semi-intensive or intensive management for cultivating it as a fruit tree have been scarce. Fruit development is characterized by a 3-year cycle since pollination to harvesting, making nutritional and hydric management highly challenging.

Materials and methods – We studied the main and interaction effects of fertilization and irrigation on growth and fruiting by a factorial design laid out in an adult stone pine plantation located in central Chile.

Results and discussion – Mineral fertilization had an effect one year later on height growth (+23.5% increase) and one-year-old conelet production (+82.3% increase). After two consecutive years of mineral fertilization, significant positive impacts on diameter growth, height growth and one-year-old conelet production were observed. Irrigation enhanced fruiting but did not impact growth significantly. The highest conelet number was observed in the fertilized and irrigated experimental plots.

Conclusion 

Both cultural practices, applied either individually or combined, are efficient techniques to enhance fruit production of the stone pine.

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This research accessed from North Carolina State University's AgriFoodGateway

Fruit Tree Pruning Focuses on Structure the First 2 Years

When I teach fruit tree pruning I divide the lessons into 2 major categories; pruning the tree for structure and pruning the tree for production.I usually give myself 3 years to establish the tree canopy. I gradually coach the tree into producing fruit by pruning.Right after planting and during the first year it's all about developing the right structure.

Fruit tree pruning classes and other classes are announced on Eventbrite/Bob Morris/Las Vegas

Three Year Progression on Pruning

Year 1:90% focus on establishing the structure.
Year 2: 50% on correcting tree structure and 50% focus on future production
Year 3: 10% focus on structure and 90% focus on production

You have 2 choices about which type of structure you want to give your fruit tree in commercial orchards; open center or modified central leader.

Open center pruning on pluot

Open Center Fruit Tree Structure

The open center structure is usually applied to peach and nectarine. While modified central leader is applied to many apples and pears. The end result is the same where pruning results in more sunlight entering the canopy of the tree. If sunlight is blocked from entering inside the tree canopy, it can result in fruits produced only on the perimeter of the canopy and not throughout it. This results in a higher percentage of fruit with sunburn and overall lower quality.
Fruit Tree Pruning Focuses on Structure the First 2 Years

Which Fertilizer to Use on My Fruit Trees and Grapes?

Q. I wonder what fertilizer you recommend for my fruit trees? The young trees I recently planted in my small orchard are: plum, peach, apricot, lemon, pomegranate, plus several table grape vines.

A. Lisa. Rather than just tell you what I would use, let me give you a little background on fertilizer selection.

To select the right fertilizer I am supposed to tell you that you should test your soil for nutrients first and then make your selection of fertilizer based upon the test results. That's the right answer but it's not always the most cost effective thing to do if you will have only a few trees. The soil test would cost about $75. You can buy a lot of fertilizer for $75. It makes sense to do this if you are a farmer and spending thousands of dollars on fertilizers and you want to get the most "bang for your buck" but for homeowners it doesn't make a lot of sense.

Mineral or Conventional Fertilizers

A reader applied wood chips around the base of the tree covering the area outlined by the tree canopy. Bender board is used in a circle to keep the wood chips away from the tree trunk while it is small.I suggest the wood chips should be at least 4 inches deep covering the soil around the fruit tree.

Most of our soils will support the use of mineral fertilizers from a bag for many years if we have the soil covered with wood chips that slowly decompose in the irrigated areas. If the fruit trees are surrounded by rock on the surface of the soil than the proper fertilizer selection becomes more critical.

Let's say you have your fruit trees surrounded by woodchips. Fruit trees planted in lawns could be put into this category as well. Just be careful of irrigating the 2 together because they have different water requirements. If the trees are surrounded by rock instead of woodchips, they are growing in the soil that's more similar to hydroponics. Fertilizer selection is more critical when fruit trees are surrounded by rock.

Numbers on the Bag of Fertilizer

Mineral fertilizers have 3 numbers on the bag. If the fruit trees are less than 3 years old, use a fertilizer that has the first and third numbers highest. The middle number, phosphorus, can be lower than the other 2. If the fruit trees are starting to produce fruit, use a fertilizer that has all 3 numbers the same value. Use this fertilizer only once at the beginning of the growing season and apply it about 2 weeks before the flowers appear. In Las Vegas, this would be about the middle of January to 1 February. For grapes, this would be about a month later.

Bag of conventional fertilizer called to Flower Power with 3 numbers denoting nitrogen, phosphorus and potassium

Application of fertilizer is frequent enough unless you have very sandy soils. But if you decide to make a second application, and the trees are surrounded by wood chips that are decomposing, only apply a high nitrogen fertilizer. This would be a fertilizer that has only the first number on the bag and the other 2 are zeros.

Another mineral or conventional fertilizer that contains only nitrogen as a plant nutrient source. This type of fertilizer should be applied less often and in smaller amounts because it doesn't last long in the soil.

Phosphorus

Phosphorus, the middle number on the fertilizer bag, sticks in the soil a lot longer than the other 2. Phosphorus is the only one of the 3 listed on the bag that can create some problems in the future if this mineral is continuously applied, over and over. This is the reason I recommend that people have 2 mineral fertilizers on hand. One fertilizer high in phosphorus, the middle number. And the other one high in nitrogen, the first number. The last number, potassium, should be as high as possible in both fertilizers. Potassium is a little bit more difficult to find in bags of fertilizers.

Compost As a Fertilizer Substitute

When you use a rich compost, it has all of the nutrients present. It is applied in a circle around the tree, about a foot away from the trunk or more, and watered, or lightly dug, into the soil. Rich compost is a very nice fertilizer and gently releases the nutrients to the plants over a long period of time. It is really my favorite to use but a good compost rich in nutrients is hard to find. 

When adding compost as a fertilizer, use a rich compost and keep it away from the trunk of the fruit tree at least 12 inches away.

Viragrow in North Las Vegas is the only place I know in Las Vegas that carries a rich compost like this. It is applied as a substitute to the first of fertilizer application. A second application is never needed and may even extend into the second growing year if enough is applied.

Changing from Lawn to Desert Landscape

Q. After 6 years of trying to have a beautiful lawn in Las Vegas, I finally give up. The water company has offered me $3/foot to convert to water smart landscaping. What should I do? Do I add more rocks and plants? Artificial turf? What trees should I use, if any?

A. If you do nothing else after removing the lawn, plant some trees or large shrubs that shade to the West and South exterior walls and windows of your home. This will help reduce air conditioning costs during the summer. These plants should be deciduous, in other words drop their leaves for the winter.

Shade South and West Walls

            Select trees that grow to about the same height as your home. Avoid trees that grow huge. They use more water and don’t really provide any extra savings in air-conditioning costs. A two-story house can handle bigger trees so in your case these should be deciduous trees so they drop their leaves in the winter and allows sunlight to warm the house. I will get back to you with some recommendations on some plants.

Sometimes just a vine on a trellis is enough to shade a wall or entrance from the hot sun.

Choose Desert Trees

I would steer you towards trees that are adapted to desert environments, in other words, “desert trees”.Regardless of the trees you select, plant them a distance from your home no closer than half of their mature height. Plant them no closer together than this either. Dig the holes for the trees at least 3 times the width of their container and no deeper. Smaller trees establish more quickly and grow more rapidly in the beginning than larger trees. Irrigate the soil around plant roots no closer than 3 foot away from the foundation of the home.

Many desert trees have excellent form and good looks like this Mesquite in this desert landscape.

Fake Grass Has Pluses and Minuses

            Personally, I don’t care for artificial grass unless it’s used for a specific purpose other than just covering the ground. It gets terribly hot during the summer if it’s in the sun and requires upkeep. If you go in that direction, start asking some questions because it is not maintenance-free. I wouldn't use artificial turf unless you have a reason to put it in. Aesthetics, or just looking at it, is not a good reason to install it. It's in the sunlight it gets exceedingly hot during the months of about April through September. It starts cooling down sometime in mid-to-late October for the fall months. If the air temperature is about 105° F, and the sun is shining directly on it, the surface temperature of your artificial grass will be about 165° F. I know because I've measured it.

Some artificial lawns look very realistic but they will be also more expensive.

Suggestions

Start appreciating open spaces. That's what concerns water deserts is open areas. Don't fill the entire landscape area with plants. Learn to appreciate what is called "negative space".

Shade the walls and windows of your home on the south and west sides. With a two-story home this requires trees 25 to 40 feet tall.

Don't plant anything closer to the house than 3 feet from it. Apply the irrigation on the side of the plants away from the house or any cement surface such as patios, driveways, sidewalks, etc.

Think of your landscape plants in multiple layers; the tall ones, the medium-sized once, small ones and groundcovers and vines.

Odd numbers of plants are usually more appealing to the eye than even numbers up to about 7 plants. Above that number, the eye doesn't seem to notice the difference.

Repeat plants through your landscape to provide some continuity and rhythm. There is no need for every plant to be different from each other. Repetition or repeating plants is a good thing and landscape design.

Vine Ripened Tomatoes Not Necessarily Healthier

Dynamic Changes in Health-Promoting Properties and Eating Quality During Off-Vine Ripening of Tomatoes

Authors: 

Mohammed Wasim Siddiqui

Isabel Lara

Riadh Ilahy

Imen Tlili

Asgar Ali

Fozia Homa

Kamlesh Prasad

Vinayak Deshi

Marcello Salvatore Lenucci

Chafik Hdider

Publisher: Comprehensive Reviews in Food Science and Food Safety     

Tomato (Solanum lycopersicon L.) fruit is rich in various nutrients, vitamins and health-promoting molecules. Fresh tomatoes are an important part of the Mediterranean gastronomy, and their consumption is thought to contribute substantially to the reduced incidence of some chronic diseases in the Mediterranean populations in comparison with those of other world areas.

Unfortunately, tomato fruit is highly perishable, resulting in important economic losses and posing a challenge to storage, logistic and supply management. This review summarizes the current knowledge on some important health-promoting and eating quality traits of tomato fruits after harvest and highlights the existence of substantial cultivar-to-cultivar variation in the postharvest evolution of the considered traits according to maturity stage at harvest and in response to postharvest manipulations. It also suggests the need for adapting postharvest procedures to the characteristics of each particular genotype to preserve the optimal quality of the fresh product.

 Author's Conclusions

The authors concluded that some of the health benefits and eating qualities provided by tomatoes increase when ripened off the vine and some decrease. It is not all bad as we are led to believe sometimes. The authors remind us that the health benefits depend upon varieties of tomato that have high health benefits in its genetics. Some tomatoes are healthier for us than others and that is not necessarily dictated by when it’s picked Vine Ripened Tomatoes Not Necessarily Healthierand storage conditions. If you want a good tomato for health benefits, choose a variety that has high health benefits to begin with. During off-vine ripening of tomato, most health attributes increase as well as eating quality. Tomato fruit is subjected to complex changes during ripening and postharvest affecting bioactive molecules and health-promoting properties, physical and eating quality-related attributes. Storage effects on tomato quality will also depend mostly on the applied treatment and temperature. Generally high quality is obtained under low storage temperature and mild storage treatment. All the above -reported changes are aiming to accumulate health-promoting compounds during ripening and to preserve as long as possible the shelf-life of the fruit during postharvest storage of tomato fruits under various conditions.

To read this article in entirety Click Here

Thanks to AgriFoodGateway at North Carolina State University for making these publications available.

Leaves Browning on Palm May Be Lack of Water

Q. I moved here a year ago and have yet to figure out what this tree needs to thrive.  I located and uncovered the drippers to make sure it was getting enough water.  I removed a lantana and a Mexican bird of paradise that I thought might be robbing it of moisture.  I think I may need to rake back the rock and provide mulch around the base.

It puts out new growth, but it soon turns brown and the tree looks pretty sad.  I thought that leaving a few of the dead fronds may provide the new growth with shade.  So far that hasn’t helped.

The tree is in the east side of the house and gets morning sun.  It is shaded by the house to the west and a large palo verde tree on the south side of the house. 

Any help would be a life-saver.  My other palms seem to be thriving, but this little guy is sick.

A. It looks like a windmill palm. What I'm looking at looks exactly like a lack of water. I hope you are not watering every day. You should give plants like this a long burst of water and then hold off before you water again. In the summer this might be 2 or 3 days apart. In the winter this could be a a week to 10 days apart.

 Windmill Palm and Drought

Windmill Palm will have leaf scorch a little bit in our climate but not that much. If that exposure is on the south or west side of the house it's probably a bad location for it because of the heat reflected off of the house and also the rock below the palm. That location can be very hot.

 What Todo

You can get some of that leaf scorch to disappear by adding more drip emitters around the palm and making sure that it gets enough water. I am guessing that your palm should receive about 15 gallons each time it's watered. I would have at least 4 drip emitters under that palm, located about 18 inches from the trunk. The amount of water depends on how many minutes the drip operates. Let's say you have it watering for 60 minutes. Then you would need for drip emitters that are 4 gallons per hour located under the palm tree. If your system is on for 30 minutes then I would have 6 drip emitters under the canopy and these are the 5 gallon per hour.

Another alternative is to not use drip emitters but a coil of drip tubing circling the tree.  .Let's again say you are running it for 60 minutes. This tubing would be connected to your irrigation supply line and be about 15 feet long. The tubing would have emitters embedded in the tubing 1 foot apart and they would be 1 gallon per hour emitters. If you are watering for 30 minutes, then use a coil 30 feet long circling the Palm multiple times. The tubing would be put under the rock. In any regard, the problem appears to be not enough water is being applied.