Plant Roots Prefer Water and Nutrients Applied to the Same Place

Q. I have read that plants grow better with water delivered to their roots, at the same spot, over and over again. Is this true?

Eggplant growing with drip irrigation in a raised bed without sidewalls.

A. Yes, it’s true but you probably won’t notice the difference. Why? Unless you compare plants growing with water applied to the same spot, over and over, with plants watered at different places you wont see much difference. 

            Plant roots get used to the amount of water and air when water is delivered to the same spots and depth, over and over. That is one reason why drip irrigation, along with the proper spacing of emitters, is so successful as long as the plant “wets its roots” to the appropriate depth each time. Watering with a hose will not as consistent.

            Water should wet the roots to the same depth every time. Small shrubs need to wet their roots to a depth of 12 to 18 inches, medium sized trees and shrubs 18 to 24 inches deep, and tall trees or shrubs should have wetted roots to a depth of 36 inches deep. This water should be applied to at least half the area under the plant’s canopy. Obviously then large plants need more water applied to them, and this water applied to a larger area, than the smaller plants.

Vegetable Seed Use and Storage

Q. I have some old vegetable seed that I planted. I was told I wasted my money and time. Do you think I did?

Vegetable seed storage for longevity depends on which seed or cuttings depending on the vegetables but maintaining an appropriate temperature and low humidity are important.

A. It depends on the seed, how it was stored and how old it was. Usually, large seed doesn’t store as long as smaller seed; maybe two or three years. Small seed might store for 5 or 6 years or longer.

            The best temperature and humidity to store seed totals less than 100. That is directly from the National Seed Storage Lab in Ft. Collins, Co. For instance, if the temperature that they were stored totaled about 70F, then the humidity should be less than 30%. If the humidity was 70%, then the temperature needs to average around 30F. Of course the best temperature and humidity for seed storage is close to freezing for temperate seed. Having them both total less than 100 is suitable for a couple of years.

            When using old seed, plant two and expect one to live is a good motto.

            When storing seed, I try to keep the temperature and humidity of vegetable seed as low as possible. I stay away from buying seed exposed to heat or direct sunlight. I use a desiccant (corn starch works okay), put them in a glass jar with a screw lid, and put them in the fridge. They will keep this way for several to many years depending on the oil content of the seed. Small seed (e.g., tomato, eggplant, beet, carrot) usually has less oil in it than larger seed (e.g., beans, corn).

Containers for Vegetable Gardening Offer Options

Q. We are planting a family vegetable garden. Would a container/raised bed do well in this environment? We're used to summers in Colorado, and wondering if there are specific tomato, cucumber, pepper, and lettuce varieties that do well here? Will root crops like carrots and radishes do well in containers? The west side of our house gets late afternoon shade from the neighbor’s house, and that is the only space we have. Would this be okay? When is the best time to plant? Soon?

A. I sent a vegetable growers Bible written by Dr. Sylvan Wittwer when he was growing vegetables in southern Nevada. Anyone interested who wants a copy can ask me for it and I will email it to you. It contains a planting calendar. He is a traditional gardener and not organic. Substitute organic alternatives if you want to use a different soil, fertilizer, or pesticide.

Container vegetable gardening offer several alternatives when growing vegetables.

When possible, use older varieties that are known successes until you get the hang of growing vegetables in this climate. When using raised beds, use compact varieties that produce fruit quickly and then throw them out and replant. Plant cautiously any new varieties. They sound cute. That’s a marketing gimmick. Sometimes they perform well in the desert and sometimes they don’t. Plant new varieties for three years in a row before calling them a “desert success”.

Want to try some root crops like radishes or beets?

If planting a “viny” plant, let the “vines” sprawl. The roots are important to the plant, not the “vines”. Keep weeds under control. Weeds breed bugs. Bugs eat plants or spread diseases. “The success of a garden equals the time your shadow passes over it.” Inspect and walk it at least daily.

Strawberries, yellow peppers, and herbs are just a few of the suggestions.

I like containers. Double pot them so they don’t get so hot when the sun shines on the outer walls. Use five to fifteen gallon nursery containers and fill them with your favorite soil to within one inch of the top rim. Put a three-inch layer of gravel in the bottom of the outer pot to keep them from lodging. If you are using tap water, filling these containers within one inch of the top will have some water coming out the bottom. This helps remove salts when you irrigate.

Cracks in Tomatoes

Q. What causes cracks in the tomatoes near the top where the stem is? I have also seen some of my tomatoes with very deep cracks. Let me know what you can tell me about this.

The types of cracks speaks volumes. Longitudinal cracks, like this one running the length of the fruit, is caused by expansion of the fruit when it is ripening. Cracking that are radial, or run around the fruit is mostly genetic.

A. There are two types of cracking, longitudinal cracks (which you have) and radial cracking (which you don’t have). Yours are longitudinal cracks. Radial cracking is mostly a varietal issue. Some varieties of tomatoes show these radial cracks more than others. If you have radial cracks, grow a different variety next season. That will lessen, but not eliminate, radial cracking.

This is a so-called "Heirloom" variety called 'Caspian Pink'. It demonstrates radial cracks typical of the variety 'Caspian Pink'. Not much you can do about it except lessen it under better conditions but the radial cracks will still be there. All type of cracks do not harm the fresh eating of these fruits unless it spoils.

            Another possibility is uneven amounts of water to the fruit. These types of skin cracking causes mostly longitudinal cracks. The swelling of the fruit and then shrinking back to its original size can cause cracking because of the expanding fruit. This type of cracking (longitudinal cracks again mostly) is lessened by using a surface mulch on top of the soil. Sometimes watering differently will help. 

Longitudinal cracking of the fruit by irregular watering even with a surface mulch of straw applied.

If you are using surface mulch, I would recommend wood or pine shavings (like rabbit, horse, or hamster bedding). It “melts” (decomposes) into the soil easier than straw which has fibers that are tough to decompose. Straw works but is more difficult to get it to break down quickly.

            You don’t need a thick layer of surface mulch but just enough to shade the ground and lessen water lost by soil surface evaporation.

Can I Use Burlap as a Shadecloth?

Q. Can I use burlap for shade cloth?

Burlap fabric 

A. Don’t use burlap as a solid piece in place of shade cloth for permanent shade. It is fine for creating permanent shade for people or pets but not for plants. Be careful how much heat it traps under it if it is located too close to humans and other animals. Plants are green and need sunlight for photosynthesis. Usually about 60 to 70% sunlight. People and pets don’t need as much.

Use Shade Cloth Instead

It comes in different percentages of shade ranging from about 30% to 100%. Shade cloth for plants ranges from 20 to about 50% shade. Plants that flower and produce fruits like tomatoes, peppers, and eggplant need more light than leafy plants: 20 to 40% shade. Shade more than this interferes with flowering and fruiting.

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This is 30% shade cloth used on a tunnel for growing sun sensitive vegetables and herbs in the desert sun in Las Vegas

Plants that only grow leaves and no flowers such as lettuce, spinach, Swiss chard, greens can handle shade up to about 50%. After 50% shade, they grow poorly. Too dark. Not enough light. Most burlap I have seen produces much more shade than this and would not be a good choice when growing plants.

 You can make 50% shade out of wooden 1x2's by omitting every other piece of wood. These are called “lathe houses”. Similarly, 30-40% shade can be done the same way but by eliminating 2 and leaving every 3rd 1x2.

Getting Asparagus Ready for Winter

Q. I've been getting e-mails about preparing asparagus ready for winter. They recommend cutting the stems 2" above the ground, then apply compost then mulch.  Is that what I should be doing to get the plants ready for winter?

When temperatures get cold and start to freeze, asparagus will turn brown, the tops die. Sometimes they stay green all winter long if we have a warm winter.

A. That’s not what I liked to do with asparagus. I found that 2 inches of “stubble” created by cutting the stems above ground interfered with my work getting ready for next year’s spring crop. I preferred to cut this woody stem growth about an inch below the soil surface with a thick knife or asparagus knife on about January 1. 

I prefer to cut the spears when I harvest them and sort them in the shed or kitchen. I find that the asparagus stubble scattered in the field interferes with walking and harvesting. https://www.harryepstein.com/asparagus-knife-usa-weeder.html?gclid=Cj0KCQiA2sqOBhCGARIsAPuPK0jTKUY5H9kiydW_sFC5-Nf8fPNb1csto5wpHWzPw97TMJAXE-aI5SoaAjRlEALw_wcB

If we have a cold winter these stems (called fronds) freeze and turn yellow. With a warm winter they stay green.

• Don’t reapply asparagus stems as a mulch to your old asparagus bed or to any vegetables due to allelopathy. I would burn it instead.

Regardless of how they appear in the winter these ferns still need to be cut back to get ready for next year’s production. After they are cut and in late winter, a fertilizer such as rich compost or regular compost plus a mineral fertilizer high in nitrogen, needs to be applied. Asparagus loves rich soil.

Bare Soil Warms Faster

Bare soil warms up faster than a cold winter soil covered in mulch. A warmer soil means an earlier asparagus spear harvest. If you can keep an eye on your asparagus emergence, then apply the mulch when you first start seeing spears if you want early production and not earlier than this. Next year’s production can start as early as January. If you want production later in the spring, then mulch them immediately after you apply the compost or manure.

Application of Insecticides Depends on the Label

Q. Please advise where I can find this borer control product you recommended to me for soil drenching. The product I found has only 1.47% imidacloprid in it. Is this strong enough for soil drenching?

A. This question opens a “can of worms” I tried to avoid earlier by only recommending a single product. Initially when evaluating a product for borer control as a liquid soil drench, two questions should be asked: 1. Does this product contain imidacloprid in the ingredients? 2. Do the instructions explain how to apply it as a soil drench to the type of plant I am treating? The instructions will tell you how to use it correctly.

Homeowner vs Professional Concentrations

            There is frequently a difference in concentrations of imidacloprid between “homeowner products” and “commercial products”. The obvious difference of course is availability to homeowners of commercial products but the other one is in the lower concentration that you mentioned.

            Homeowner products are frequently less concentrated than commercial products. This is because commercial applicators should have more knowledge about safe use of these pesticides and access to PPE (Professional Protective Equipment) when applying it. Plus, the homeowner uses less product.

            For commercial applicators, imidacloprid is contained in several products and atconcentrations much higher than 1.47%. “The dose makes the poison” and having a less concentrated product available to homeowners can be “safer” for the uninformed to use. It also means less “left over” product when finished.

Read the Label

            Is 1.47% strong enough to use as a soil drench?  Look at the directions for use. Does it say you can use it as a soil drench for your purpose? A reliable manufacturer will want you to be successful, tell others about your success and use their products again. A reliable manufacturer will give you the right instructions and concentration that will be effective.

This formulation of imidacloprid allow for a soil drench of vegetables and fruit trees. It has 0.233% imidacloprid and the label tells you how to mix and apply it. If the label doesn't allow it, then by law it is not allowed.

            It’s up to you to read the directions and make sure this product is applied correctly as a soil drench and for your purposes. Make sure it is applied after the plant flowers in the spring to avoid “honeybee” problems which it clearly states on the label.

Starting a Fall Vegetable Garden

Q. Could you help me get a fall garden going? Please send me a list of crops that grow in Las Vegas. I live in the northwest area off of Ann Road and Jones in Las Vegas

A. I posted a calendar for planting in the fall on my blog. Download a copy there but I will give you a rundown of the crops which are normally started this time of year in the eastern Mojave Desert.

            First, some background. There are two planting times each year. Plant cool season vegetables and herbs that withstand frost and cold during the late summer, fall, winter and spring months. Plant the warm season, winter-tender vegetables and herbs when danger of frost has passed and into the mid-summer months. Warm season crops die or perform poorly during cold or freezing weather.

            Even though it’s still hot now, this is the time of year to plant several fall and winter crops. Notice that I said many, not all. Exact planting dates vary with soil and air temperatures, the time plants require before they are ready to harvest as well as the quality of the end product.

            Cool season crops that require 60 or more days before harvesting will be just fine if planted now. It is too early to plant crops like radishes which are ready to harvest in 30 days.            

            Exact planting dates vary with your garden microclimate. Gardens located in warm microclimates have different planting dates from those gardens in cooler microclimates. If you are lucky enough to have a landscape with more than one microclimate, you can stagger your planting dates so that the same crops mature a few days or even a week or two apart.

            Plant gardens that face West or South later in the fall but earlier in the spring. Gardens facing east or north are planted in the reverse order.

            The following vegetables can be planted during September from seed or seed pieces for fall, winter and spring harvest: beets, broccoli, carrots, collards, endive, Irish potatoes, kale, kohlrabi, lettuce, peas, rutabagas, spinach and Swiss chard.

            The following could be planted as small transplants: broccoli, Brussels sprouts, cauliflower, cabbage, celery and Chinese cabbage. If temperatures are unusually hot, delay putting in transplants until weather cools off a bit.

            Mulch the soil to keep the seeds and roots of transplants moist and cool.

Yes. You Should Fertilize Plants During the Summer

Many people believe you can't or shouldn't fertilize during the summer months. That is incorrect. Fertilizers are important to apply when plants need them, not according to the weather. The reason people are told not to is because fertilizers can be more dangerous to plants during hot summer months.

This is how you can and should fertilize during the heat. It is not magic. It is common sense.

 Ammonium sulfate can burn plants, is fast in its release and dissolves totally in water. I use it but you must be very careful using this fertilizer in the summer.

The major problems with fertilizing during summer heat is the combination of high temperatures and fertilizer salts. Salts in fertilizers can be damaging alone but in combination with high temperatures, they can be lethal. The amount of fertilizer you can safely apply is much higher in cooler months than in hotter months. You are not going to change the temperatures, but you can apply less fertilizer.

Rule No. 1. Apply less fertilizer during hot weather. 

Salts are all around us. They are in the food we eat. They are in the water we drink. They are in the soils we use to grow vegetables. Most organic fertilizers release fertilizer salts more slowly than conventional fertilizers. Not always, but generally speaking. So using organic fertilizers is usually a safer thing to do than using conventional fertilizers.

Rule No. 2. Use organic or slow release fertilizers during hot weather.

Fertilizer salts are salts. Salts can damage plants in two ways. First, drying out plant roots and stems through dessication or pulling water out of the stems against the desire of the plant to keep water inside the stems. Salt applied to living tissue pulls water out of the tissue. This type of damage to plants is much more severe when soils are dry. Never apply fertilizers to dry soils during summer months. When you are finished with a fertilizer application, water the fertilizer into the soil.

Blood meal is an organic fertilizer, safer to use than ammonium  sulfate but you still need to be careful.

Rule No. 3. Irrigate soils first. Apply fertilizer next. Then water in the fertilizer.

Fertilizers applied 1 to 2 inches next to the stems of plants can damage or kill. Salts in fertilizers pull water out of stems. If fertilizer is accidentally applied too close, don't panic. Either scrape it a few more inches away from the plant or push the fertilizer away with a stream of water and water it in. Apply fertilizers near the water source and no closer than 4 to 6 inches from small plants. Whether you think dry fertilizer landed on plant leaves or not, it is always safest to wash the leaves with water after a fertilizer application.

Rule No. 4. Keep applied fertilizer a safe distance from plants.

Temperature is important when fertilizing plants. Apply fertilizers in the cool morning hours or when there is a break in the summer heat.

Osmocote is a slow release conventional fertilizer but a safer fertilizer to use in summer months.

Rule. No. 5. Apply fertilizers to plants during the cooler times of the day.

Vegetable and Herb Planting Calendar Re-Posted as PDF

I made some changes in the one I posted earlier and embedded it from Scribd as a pdf document. Please let me know if you have trouble downloading it by posting here on the blog. This has been put together for elevations of about 500 ft (160m) to 3000 ft (1000m) elevations at 36 degrees N. Latitude in a desert environment.

Vegetable and Herb Planting Calendar

Microphotography of Fruits, Vegetables, Spices and Grains

Q. For the past few years I have been taking microphotographs of fruits and vegetables. One of the factors that has an impact on the quality of the image that I am able to get is the freshness of the fruit or vegetable. Are you aware of any source or sources that I could contact that grow produce here in southern Nevada? I am interested in all produce but especially interested in grains and spices.Thank you in advance for any information you may be able to email me.

Robert Belliveau

rrobbell@aol.com

See some of Robert Belliveau's microphotography

A. Robert,

There are local producers. The best place to meet them is at the Farmers Market at the Las Vegas Springs Preserve on Thursday mornings from about 10 am to noonish. They will be growing things that will bring them the most money, highest demand and grown with relative ease. This usually precludes grains and spices. Most grains require a fairly large volume and spices are a possibility but they have not gotten into that market yet to my knowledge. Most spices are tropical or at possibly subtropical and a bit difficult to grow in southern Nevada without protected culture of some sort. But I would suggest you start at this market. Wish you the best.

With Robert's permission I have included his email above if you would like to contact him directly regarding the availability of fresh grains and spices in the Las Vegas area.

Open publication - Free publishing - More las vegas

March Todo List in the Orchard



Sweet corn at the orchard

March Todo List

• Plant sweet in at least three rows for wind pollination. Plant seed one foot apart and enough room between rows so you can harvest ears. Keep out of strong winds.

Contessa sweet onions after harvest
at the orchard

• Dig and replant onion transplants or plant transplants ordered. Be sure to use a high phosphorus fertilizer and compost at the time of planting. We can grow both Short and Long Day onions. Try Candy, Big Daddy, Texas Super Sweet, Red Candy, Walla Walla, Sterling. A good place to order online is Dixondale Farms in Texas http://www.dixondalefarms.com/     

• Harvest asparagus every 2 to 3 days. Store spears upright to prevent curving of the spears.
• Tomatoes, peppers, eggplant, melons, cucumbers to be planted March 15. Protect from wind and strong sunlight for two weeks.
• Early March. Prune table grapes.
• Spray to prevent thrips damage on nectarine fruits.
• Prepare bottles for putting on fruit trees for harvesting fruit in bottles. Select early producing varieties and put the bottles upside down so they drain and in the shade of the canopy on the north side.

Growing fruit in bottles partially covered with aluminum
foil to prevent heat buildup



• Weed vegetable plots.
• Cutworm control on newly emerged seedlings. Spray Bt (Dipel or Thuricide) or Spinosad over newly applied vegetables and the soil surrounding the plants.
• Prune palms to get them out of the way of the vegetable plots.
• Harvest green almonds toward the end of the month and into April.
• Thin apricots when dime sized.
• Thin peaches when nickel sized.
• Harvest snow peas
• Fix irrigation leaks

Almonds harvested green. This size and smaller can be used.

Harvesting Herbs and Easily Damaged Vegetables

Nothing is worse than harvesting herbs and eggplant and by the time you get them in the door they are withered or soft and no longer firm. Or your products didn't last very long in the cooler. Here are some suggestions on how to harvest these tender plants from the garden and keep them fresh.

The ideal time to harvest most herbs is as early in the morning as possible. This is the time of day when temperatures are lowest, humidity is highest and winds are low. This is also the time for herbs when those volatile oils that are so important are at their peak and flavors are best. Harvesting should be at a time when the flower buds are just starting to form but before they open. When the flowering cycle begins, the plant begins to shove nutrients at the flowers and subsequent seeds which takes precedence over the production of leaves and stems. Flower formation indicates this loss of nutrients in leaves and stems is about to happen. After some familiarity you will begin to visually predict when this occurs as you note changes in the growth of the plant.

If at all possible, spray herbs and soft vegetables with a mist of water 10 to 20 minutes before harvesting to wash dirt from the surface, cool the plant down and rehydrate the surface. In the case of vegetables, the larger the vegetables the longer it takes to cool the plant down. So don’t expect that a quick rinse of eggplant for instance to have much impact in cooling the fruit down internally. In our dry climate the cooling effect from spraying a plant down with water may last ten minutes at best and then the temperature begins to climb back toward the air temperature quickly. On the contrary, a light mist of water on the surface of most delicate herbs and leafy vegetables will cool the plants down considerably.

Make sure you take a clean bucket with cool, clean water (non chlorinated would be best) into the field with you. During summer months the water temperature should be at least cool to the touch and cooler than the air temperature. For those requiring more exacting guidelines you should have temperatures about 55 to 65 F. There are some plants that can be packed in ice while others cannot. Icing is usually reserved for cold hardier plants like broccoli, spinach, cilantro, parsley, green onions, and Brussels sprouts. Icing more tender plants will result in injury.

The four major enemies to plant quality and storage life occur after harvest: damage from handling, low humidity and water loss, high temperatures, and direct sunlight. Do everything you can to keep these enemies from damaging your harvest.

Damage from handling. Harvesting requires a sharp and sterile knife or shears. Herbs and soft vegetables should be severed from the plant cleanly without tearing or ripping and lifted rather than pulled and immediately immersed in clean, cool water. Any surface tearing or scarring impacts the quality of herbs and soft vegetables and their storage life. If you have long fingernails or wear jewelry on your hands that could tear or rip, wear thin plastic gloves to protect these tender plant parts from damage. This may sound like these precautions are “overboard” but if you expect to store these plant parts for any length of time, damage to the surface of the plant allows water to be lost and disease pathogens entrance. All herbs and soft vegetables have to be inspected for damage and sorted for quality. Sorting or grading of products, if not done carefully and out of harsh conditions, can intensify damage and result in even more losses.

Low humidity and water loss. Our desert climate is naturally low in humidity. That is great for growing plants but not so after harvesting. As soon as the herbs or vegetables are severed from the plant its source of water is removed, air enters the stems, water no longer moves through the severed plant part. Plants with roots attached can lose water from leaf and stem surfaces and water from the roots replenishes lost water. This keeps the leaves and stems hydrated and cool. Evaporation of water from leaves and stems helps cool the plant. As water is lost from severed plant parts their freshness and quality is compromised. Immersing them in cool, clean water immediately after harvest helps keep these products hydrated and fresh. Keep these plant parts out of the wind, direct sunlight and high temperatures which drive excessive water loss.

High temperatures. It should go without much explanation that harvested plant parts should be kept cool unless you are dealing with vegetables that require high temperature and humidity after harvest such as sweet potatoes.

Direct sunlight. The energy from the sun can be deceivingly destructive. I don’t know how many times I have told people in the field to put harvested products in the shade, even if it is under the shade of other plants. This is one of the most commonly abused practices after harvest. I observed small-scale producers in Kenya on the slopes of Mt. Kenya harvesting products and putting them in direct sunlight to be picked up by the co-op truck a few hours later. To top it all, these products were sorted and graded at the co-op headquarters by co-op members in DIRECT SUNLIGHT! Coop members then did not understand why half or more of their harvest was rejected by the exporter.

Cleaning. A light salt solution (two tbs per five gallons or 35 g. per 20 L) can clean products of insects without damaging plant parts. Straight table salt, sodium chloride, has two chemicals that can cause plant damage; sodium and chloride ions. If too intense, damage will result. A better salt might be a potassium based salt rather than sodium which can be very toxic to plants. Immerse the plant parts in salt water, remove and dry in a salad spinner and place in a sealed container with a sterile, wet blotter and in a cool location out of direct sunlight. Herbs can be dried completely by blotting with paper or soft towels.

Storage. Storage temperatures for most herbs is close to freezing but not below freezing and humidity as close to 100% as possible. Refrigeration (41F or 5C) is next best loses about one week of storage life compared to near freezing. Freezing damage appears as darkened translucent or water-soaked areas. These areas deteriorate and wilt rapidly after bringing to room temperature and ruins the product. Expected shelf-life is 3 weeks at near freezing (32F or 0C) and 2 weeks at 41°F or 5C.

http://postharvest.ucdavis.edu/Produce/ProduceFacts/Veg/herbs.shtml.
I have noted shelf life longer than this in locally grown products when handled correctly.