WHAT CAUSES BOLTING IN PLANTS?

WHAT CAUSES BOLTING IN PLANTS?

Submitted by ~ Sheri Kisch

I had planned to answer this question, plain and simply. Bolting in any plant is not plain or simple. I and others just want to know why the spinach is bolting at 2” tall and another year it doesn’t bolt till July. And what’s up with mums in full bloom in July?

“Bolting is the premature production of flowers, especially of vegetables usually triggered by environmental or cultivation factors” according to the Dictionary of Gardening.

bolting 2That being said I found that many things rule bolting in plants. To start, it can be induced by plant hormones. Really! Gibberellin regulates different developmental processes that include germination, stem elongation, dormancy, flowering and flower development. When plants are exposed to chilly temperatures more GA’s are produced. You can see how cold wet spring weather can start the process.

Bolting can sometimes occur from changes in day-length called photoperiodism. The critical day length for spinach is 13 hours. So when I planted seed in May, I would already be behind as the May day-length is at 14 hours. My row of spinach that was left to seed on purpose, then chopped up and turned under for mulch. It started growing last fall. It was very hardy – but – it was also very cold with a rainy spring that triggered the GA’s which in turn started senescence. The plants already had small flowers forming at 2” high. You can find calendars and charts online that give day length and critical hours. Scientists have long thought it was the length of daylight that made differences in plants. They have now found that the amount of complete darkness is what makes the most difference.

Take a deep breath. Ok, you have heard about planting by the moon. We now go into a whole other realm. Root crops are planted in the dark of the moon and above ground vegetables are to be planted in the light of the moon. The moon controls gravity, which influences soil and water. The Old Farmer’s Almanac is a good source of information.

bolting 1Senescence is the aging process of a plant or part of a plant. Trees are a good example of senescence because of the amount of leaves changing color and falling off, dying. Sometimes it’s a natural process or it can be caused by environmental factors such as day length and season change. It can be triggered on only part of the plant due to pests, disease or drought. The plant can shut down the part that is diseased to save the whole plant or tree and prevent disease from spreading. All natural senescence is regulated by hormones.

There is so much more about bolting for me to learn and tons of information out there. Using your favorite search engine, type in bolting, photoperiod, day-length, moon phases, or senescence. This is where level 2 & 3 come in laying the ground work. Dara Palmer gave me some good extension websites.

https://horticulture.oregonstate.edu/oregon-vegetables/spinach-0
https://extension.oregonstate.edu/news/tired-bolting-spinach-plant-while-soil-cool
https://web.extension.illinois.edu/veggies/spinach.cfm

Do trees heal?

Submitted By ~ Corry Mordeaux

Guess what? They do not!

Wait a minute…I prune my tree and the wound heals up. Nope! Let me introduce you to the funny abbreviation “CODIT”. This stands for Compartmentalization Of Decay In Trees. OK, this is pretty fuzzy. Let’s dig a bit deeper.

We need to look at trees as being a tree within a tree. Each annual ring that you see in a cross section is actually a tree. (Illus. 1 below)

trees 1

Illus. 1

trees 2

Illus. 2

 

 

 

 

 

If we look at a cross section of a tree, we see the annual rings (tree within a tree) but we also see ray cells from the center to the outside. (Illus. 2 above)
Now hold those two pictures in your mind for a moment. As you well know, animals heal or restore a wound or infection to a healthy condition. Trees wall off or compart-mentalize injured tissues. Trees have no healing abilities. They wall off or isolate the injury. With the previous pictures in mind, CODIT is based on “walls” …top, bottom, and sides. These walls are in the growth rings and are penetrated by “tubes” (vessels or tracheids).

Some organisms and insects are able to continue to work through the walls. The cambium forms the most important barrier wall separating infection from new wood. This new wood is seen growing around a wound.

A good example of CODIT is provided by the reference for this article. “trees 3Another way to look at this situation is to show how it is similar to a battleship. A battleship is a very slow moving vehicle. It is highly compartmented. When it is hit the survival of the ship depends on the ability of the crew to close off the areas hit by a shell or torpedo. When the crew is very active and the ship has preset construction that permits effective walling off, the ‘injury’ can be limited to a small space. But, if the crew is sluggish, and the preset construction of the ship is weak, then the injury could cause severe problems – the ship could sink.”

The basis and diagrams for this article come from the National Arborist Association Home Study Course and is based on research conducted and published by Dr. Alex L. Shigo.

 

Gardening Advice or Myth (GAoM): Weeding out Fact from Fiction

Gardening Advice or Myth (GAoM): Weeding out Fact from Fiction

Submitted by ~ Suri Lunde

Below are a few gardening advice/myths that we often hear but may or may not be solidly rooted in science or actually work.

GAoM 1: Compost adds lots of nutrients to soil.
It is true that adding sufficient compost into gardens makes plants grow well, which somehow implies that compost must be adding nutrients to our soil. In reality, compost has dismal nutrient levels: an N-P-K analysis of 1-1-1 or less. What compost actually does is help plants grow better in low nutrient environments by increasing the population of bacteria and fungi in the soil. These bacteria and fungi take the not-fully decomposed matter in the compost and convert them into specific nutrients the plants need to grow. So go ahead and apply lots of slow-made well-aged compost regularly and create a perfect habitat for the bacteria and fungi so that they do your fertilizing.

GAoM 2: Gravel in the bottom of containers helps drainage.myths 1
It is standard practice when filling a container to place gravel stones or pieces of pot at the bottom ‘for drainage’. This actually restricts plant growth because it has less space, and also results in roots sitting in water. Water clings to soil particles until it is completely saturated, then drains away. A layer of gravel at the pot’s base only collects that water and shifts the pool of water higher up the pot, making the roots sit in it and causing root rot. As long as there is a hole at the bottom of the container, water will find its way out without the need of gravel.

GAoM 3: Always plant marigold in the garden.
Many gardeners plant rows of marigold along their vegetable patch or as a companion plant because marigold repel many garden pests and insects. Marigold helps reduce, not eliminate, nematodes (microscopic worms) in the garden. Although many nematodes are beneficial (e.g. they help kill June bugs in lawns), some nematodes invade plant roots and cause deformities in root crops like beets and carrots. Marigold acts as a repellant for nematodes: its natural nematicides kill the nematodes, and chemicals released by its roots prevent nematode eggs from hatching, thereby decreasing the nematode population. The marigold’s fragrance does not play any part in attracting or repelling nematodes or any other pest – that is a myth.

GAoM 4: Watering plants in the afternoon sunlight burns leaves.
The belief is that water acts as a magnifying glass, focusing the sun’s rays as they hit the water, causing ‘leaf burn’. If this is true, farmers would suffer massive losses after each daytime rainstorm! Using computer modeling and live tests, scientists have proven that water is not powerful enough to magnify the sun’s rays to the required heat needed to burn the leaves on plants. Generally, the best time to water most outdoor plants is early in the morning but if watering in afternoon sunlight is the only option, it will not harm plants.

Conclusion: Let’s promote truthful gardening wisdom and debunk gardening myths. By letting unequivocal gardening myths die, we all gain a better way to grow showy perennials, overflowing hanging baskets, and bountiful vegetables.

Black Walnuts – Do Black Walnut trees really poison other plants?

Submitted by ~ Corry Mordeaux

Do Black Walnut trees really poison other plants?DR. Bob

Yes. Many plants are killed when grown within the root spread of the black walnut tree. Butternut and Persian walnut trees grafted onto black walnut rootstocks give the same effect.

Black walnut trees contain a phytotoxin, juglone, which remains in the roots and is not secreted into the soil. For injury to occur the roots of the walnut must contact the roots of other plants growing nearby. Plants closest to the walnut tree are usually injured first but plants up to 80 feet away can be injured because that is the average root spread of a mature black walnut tree. Even after the walnut tree is removed, juglone may remain in the dead roots until they decay.

The wilting caused by a plant’s contact with juglone cannot be reversed or reduced by watering. Stunting, death, or wilting of the whole plant or only a part of it may occur. The side nearest to the walnut tree usually wilts first. Although most plants are affected, even other walnut trees, the problem is most severe on tomatoes, potatoes, and evergreens.

Note: I have a 30 foot Pinus sylvestris (Scots Pine) that is very dead. It was planted about 15 feet from a Black walnut. (Not too smart, Corry.)

Dr. Bob is gone but his wisdom lives on.

The Suburban Micro-Farm: Modern Solutions for Busy People

The Suburban Micro-Farm: Modern Solutions for Busy People

by Amy Stross

Submitted by ~ Elizabeth Waddington
Illustrated liberally with photographs, the book includes chapters on developing healthy soil, landscaping with edibles, and even permaculture. I’m pretty taken with the herb spiral project. Stross includes Life Hacks such as #1: Spend 15 minutes a day (to keep from being overwhelmed). While the author lives in Ohio, the information is applicable to our Montana growing conditions. She includes a variety of extenders for both shoulders of our short summer growing season and gives advice about no-till gardening techniques. Loaded with practical info!

(available from Amazon)

The Hidden Life in Soil

The Hidden Life in Soil

Submitted by ~ Ann McKean

As Master Gardeners, we know all about soil texture, pH, cations, nutrient and water holding capacity and how all these things affect soil’s ability to support the plant life above it. But there is a whole world of life in the soil which is mostly out of sight, and for most of us, out of mind. Apart from insects and other invertebrates which live in the soil, there is another form of life which plays a vital role in the health of the soil and the plants we love so much, and ultimately the health of every living thing including us. That life is fungi.

When we think of fungi we usually think of mushrooms, but these are only the fleeting fruiting bodies of mycelium, the vegetative body of fungus and the foundation of the food web, which forms a vast underground network and creates the rich soils we depend on for life. In fact, scientists believe that one of the largest (and oldest) single life forms on earth is a fungal network found on a mountain in Oregon. These fungal networks break down matter through decomposition and make nutrients available in soil. Without them, we would be buried in un-decayed matter.

The three general types of fungi are parasitic, saprobic (decomposers) and the mycorrhizal and endophytic (mutualists). Powdery mildew is a good example of a parasitic fungus which breaks down a living host. The cultivated mushrooms that we consume are saprobic fungi which live on dead organic matter; however, the most amazing type of fungus is mycorrhizal, which forms a symbiotic relationship with plants. As the mycelium of mycorrhizal fungi grows through the soil, it forms connections with the roots of plants and supplies available water and nutrients such as phosphorus to the plants. In exchange, the mycelium receives photosynthates such as sugars which it needs but cannot produce. It even stores these carbohydrates (a form of carbon sequestration) and releases them back to the plants in times of need. And mycelia not only help one particular plant, but they form a bridge between plants which transfers chemical information and nutrients back and forth between the plants, often allowing stronger plants to direct more nutrients to weaker plants. Scientists believe that over 90% of all plants have a natural mycorrhizal relationship and as a result these plants are more resilient to fluctuations in weather and even to the effects of climate change.

Just as we benefit from a healthy microbiome in our gut to digest our food, so does mycelium. Mycelium is a powerful digestive membrane with the ability to break down toxins in our environment, but to maintain healthy soils full of life, we must be thoughtful about the substances we use in our gardens. While chemical fertilizers and pesticides offer rapid gratification, they can often weaken and even kill the fragile microbiome in the soil. This, in turn, creates a cycle of dependence on these chemicals. The way to restore the healthiest possible soil (and plants) is to mimic nature and use gentle natural organic materials which protect the microbiome while feeding the complex mycorrhizal networks which have evolved to nurture our plants and the vast community of life in the soil. This promotes a healthy balance in our gardens and our environment.

By understanding and supporting the complex hidden community of life in the soil which depends on the miracle of mycelium, we can intentionally and actively contribute to the resilience and sustainability of our own communities and our planet.