Rotation Makes Gardens Go Round

Corn is a consumptive summer vegetable.

Vegetables are greedy as they grow. They crave rich soil. They exploit it and abandon it at the end of their season. Nutrient depletion can be a problem for subsequent phases of similar vegetables. In other words, vegetables of any particular family consume the same nutrients. Each phase leaves a bit less for the next. Crop rotation disrupts this process.

Different types of vegetables deplete different types of nutrients. This is an advantage for a vegetable garden. Tomatoes can deplete soil nutrients for subsequent tomatoes. Corn, however, may not notice such depletion. It craves different nutrients, so may be content with what tomatoes did not consume. This is how and why crop rotation is so effective.

Crop rotation is simply a technique of not growing vegetables where similar types grew. Vegetables grow better where different types grew previously. Their formerly depleted but vacated soil can recuperate in their absence. They can return to the same soil after three years or so. Other vegetables that grow there for that time accelerate recuperation.

Warm season vegetables are generally more consumptive than cool season vegetables. That is because so many of them are actually fruits, such as tomatoes, corn and squash. More cool season vegetables are truly vegetative, such as lettuce, cabbage and carrots. Because they produce no bloom, seed or fruit prior to harvest, they need less resources.

Therefore, warm season vegetables are more responsive to crop rotation. Most are not relatives of the cool season vegetables that they are now replacing. Similar vegetables of the previous few summers are more of a concern. Tomatoes, eggplants and chilis are all of the Solanaceae family. They should avoid soil that their relatives used previously.

Similarly, if possible, corn should not grow where it grew within the past few years. Nor should beans. Fertilizer can compensate somewhat for soil depletion where rotation is impractical. For example, a fence may perpetually be the ideal support for pole beans. Spring lettuce, carrots and other vegetative vegetables may be less reliant on rotation. Although most squash benefit from rotation, zucchini seems to be productive regardless.

Soil Is More Than Dirty

Soil amendments improve percolation of moisture.

All weeds are plants. Not all plants are weeds. Weeds are a specifiable subset of plants. Specifically, weeds are plants that grow wildly where they are undesirable. Similarly, dirt is likely soil, although it could be anything that is dirty. Soil is not merely dirt, though. Dirt is soil or a similar matter, where it is undesirable. Plants and weeds know the difference.

Most simply, soil is the loose material on the surfaces of most land. Obviously, looseness is relative. Some is quite dense and hard. It is not solid rock though. All of it consists of a combination of various inorganic aggregates. Most also includes various organic matter. Inorganic aggregates range in size from microscopic clay particles to substantial stones.

Soil provides stability and nutrients for vegetation that inhabits it. Roots disperse through it for structural support of their associated stems and foliage. Roots also absorb nutrients and water, as well as conduct respiration. Soils are naturally quite diverse. Vegetation is naturally more diverse to exploit various soils. Very few soils can not sustain vegetation.

Lawns are the carpets of a garden. Hedges are the walls. Tree canopies are the ceilings. Soils are the foundations. They support all vegetation that is not self-reliant in containers or epiphytically. Some soils are sandy, so drain very efficiently. Some are denser clay, so may drain slowly. Like climate and exposure, soils can limit what grows within a garden.

Most common and popular vegetation is satisfied with most common types of soil. Some, particularly vegetables and annuals, are more demanding. Even within good quality soil, they appreciate amendments such as compost. Amendments improve aeration, drainage and moisture retention. Organic amendments also provide nutrients as they decompose.

The most demanding vegetation also appreciates fertilizers. Most fertilizers are chemical or synthetic fertilizers of very precise formulation. Organic fertilizers are only slightly less precise. All allow application of specific amounts of specific nutrients for specific results. For example, nitrogen enhances foliar growth. Also, phosphorus enhances floral growth, and fruit growth.

Crop Rotation Promotes Garden Efficiency

Squash eventually depletes particular soil nutrients.

Maya Angelou likely enjoyed gardening. She said, “In diversity there is beauty and there is strength”. That is how the healthiest of ecosystems, including home gardens, function. Vegetable gardens are generally diverse. However, each group of a particular vegetable is rather homogenous. Crop rotation can compensate with diversity through the seasons.

Crop rotation is growing different vegetables in particular places from season to season. It is the same as growing particular vegetables in different places from season to season. Distinctly consumptive vegetable plants should relocate each season. Less consumptive sorts may perform adequately in the same place for years. Diversity makes it interesting.

Each type of vegetable plant consumes particular nutrients from the soil. Eventually, they can deplete their soil of these particular nutrients. Crop rotation allows them to utilize the nutrients they need from undepleted soil instead. Meanwhile, other vegetable plants can grow in the vacated soil. These different types of plants utilize different types of nutrients.

For example, tomato plants notoriously deplete the soil of particular nutrients. Corn does the same. However, each depletes different nutrients. Therefore, corn can be satisfied in soil vacated by tomato plants. Likewise, tomato plants can be satisfied in soil vacated by corn. Furthermore, each promotes the restoration of the soil nutrients needed by the next.

Crop rotation also disrupts proliferation of several pathogens that infest vegetable plants. Dormant spores of bean rust disease overwinter in the soil beneath infested bean plants. They efficiently infest any receptive bean plants to occupy the soil during the next spring. However, they can not infest plants that are not related to beans, such as pepper or okra.

Summer vegetables should be situated accordingly as they return to vegetable gardens. Tomato, pepper and eggplants are related, so should not grow where any grew last year. The same applies to bean and pea. Squash and cucumber are related also, but are less consumptive. They may perform adequately within the same soil for more than one year. Several summer and winter vegetables are related.

Mulch Retains Moisture And Insulates

Mulch helps to insulate the soil.

Nature is smart. It should be. It has been operating efficiently since the beginning of time. That is certainly longer than anyone has been gardening in defiance of nature. Imported plants that need unnatural watering and soil amendment continue to benefit from nature. Some assets, such as weather, are direct from nature. Some, such as mulch, are copied.

Summers are long, dry and somewhat warm here. Without rain, there is plenty of time for the soil that roots inhabit to become dry. Warmth and aridity increase the consumption of moisture by plant species that are not accustomed to such extensively dry weather. That is precisely why landscapes and home gardens are so reliant on supplemental irrigation.

Because water is expensive, plants that do not require much of it are popular. Automated irrigation systems should operate as efficiently as possible to minimize waste. Since turf grass is very consumptive, lawns should not be overly expansive. Conservation of water is common here. There are several techniques for doing so. Mulch is one of the simplest.

Although adding mulch to a garden is unnatural, it works like the natural detritus within a forest. It retains moisture and insulates the surface of the soil. Without mulch, surface soil can become uncomfortably dry and warm for roots. Mulch also inhibits the proliferation of weeds. Because weeds consume moisture, their absence indirectly conserves moisture.

Mulch generally goes into the garden during early spring, before weed seed germinates, and after the removal of the detritus of winter. It can be practical at any time though, even as the soil becomes dry and dusty through summer. Various forms of mulch are available from garden centers. Home compost works splendidly, but costs nothing more than labor.

Alternatively, several types of groundcover can function as mulch. Some types consume more moisture than they conserve, but exclude weeds. Some types, such as ceanothus, lantana and licorice plant, might not crave any more water than the plants they surround. Their maintenance should involve less effort than removal of weeds which they displace. They are more visually appealing anyway.

Saturation Of Soil Distresses Roots

Some riparian plants tolerate soil saturation.

Saturation of the soil should be a rare problem within the local chaparral climates. Water is a limited resource. That is why plants that are not native or endemic to other chaparral or desert climates rely on supplemental irrigation. Many exotic species would not survive through the locally long and dry summers without it. Water is only sufficient during winter.

The unfortunate reality is that soil saturation is among the more common problems within landscapes that rely on gardeners. Although most gardeners are proficient with irrigation, some are not. They would prefer to irrigate too generously than risk desiccation. They do not assume the expense of the water, or of the plant material that succumbs to saturation.

Although significantly less common within home gardens that do not rely on professional gardeners, soil saturation is possible. It occasionally happens within pots or planters that lack adequate drainage, or if the drainage becomes clogged. Saucers that contain water that would otherwise damage decking or flooring might inhibit drainage if constantly full.

Besides within pots and planters, saturation is more likely within dense garden soil than within coarser soil. Downspouts could saturate surrounding soil through the rainy winter season. Leaky plumbing might do the same at any time, even if it is merely irrigation pipe that leaks only while operating. Of course, excessive irrigation produces most saturation.

Saturaturation deprives soil or medium of aeration. Roots avoid soil or medium that lacks adequate aeration. Trees and large shrubbery therefore disperse most of their roots near the surface of saturated soil. Such shallow root dispersion limits stability. The expansion of such shallow roots displaces and fractures pavement and curbs, and heaves lawn turf.

Excessive irrigation causes soil saturation during summer. Excessive frequency is more likely to cause saturation than excessive volumes of water. Unfortunately, it is impossible to prescribe appropriate irrigation schedules and application rates. Climate, soil type and plant material are all relevant considerations. Moisture requirements change seasonally, and from year to year, as plants mature.

Edelweiss – Fail

P00627K
‘Small and white, clean and bright’? They only got as far as ‘small’ and ‘clean’, but did not get to ‘white’ and ‘bright’.

Edelweiss, edelweiss, every morning you greet me. Small and white, clean and bright, you look happy to meet me. Blossom of snow, may you bloom and grow, bloom and grow forever. Edelweiss, edelweiss, bless my homeland forever.”

Why are there no corny songs like this about California poppy?

Although I never met edelweiss before, I always thought that it must be quite excellent. Those who are familiar with it where it grows wild in European mountains seem to believe so. It does not look like much in pictures, so must be much more impressive if experienced directly.

A colleague here who met it directly in Austria decided to grow some, and easily procured seed online. The seed was chilled in a freezer to simulate winter in the Alps, and sown just prior to the last of the rain as winter ended. They germinated, and the seedlings started to grow, but then mildewed. The potting soil that they were in was likely too rich and too damp.

After all, edelweiss naturally lives in limestone scree, where the climate is harsh. Such environments are less than hospitable to fungal pathogens that cause mildew. Rich and well watered medium that would be considered to be a good situation for so many other seedlings may not be what edelweiss seedlings are comfortable with.

There are already plans to try edelweiss again next year. Seed might get sown in sandier medium, and a bit later in the year, so that they are not so regularly dampened by rain. If they survive beyond their seedling stage, they will likely become more resilient as they get established in an appropriate landscape. There are a few situations here where sandy soil drains well.

Perhaps I will eventually experience edelweiss, and see what all the fuss is about.

Mulch Is Imitation Of Nature

91113thumbEvery living thing in our gardens came from the wild somewhere. A few plants might be natives trying to adapt to synthetic landscapes. Some might be from similar climates. Some are likely from very different climates. Even houseplants came from the wild somewhere in the World. Regardless of their respective origins, in home gardens, all plants want to behave as they would in the wild.

Many plants want to defoliate at this time of year. Even some evergreens want to shed some of their old foliage before winter. Some perennials die back to the ground. Most summer annuals are already dead. There is an abundance of deteriorating organic material getting discarded by the plants that produce it. In the wild, all this detritus would naturally fall to the ground and decompose.

That might be a problem in parts of our refined landscapes. Fallen leaves must be raked from lawns, decks, pavement and various other flat spaces outside. If left too long, they shade out lawns, ground cover and bedding plans. Fallen leaves can stain decking and pavement too. The worst diseases of roses and fruit trees overwinter in fallen infected debris that does not get raked away.

Unfortunately, raking the mess of autumn away deprives the plants that live in the garden of the abundant decomposing organic matter that they expect to be delivered this time of year. The soil is left exposed and uninsulated, allowing temperature and moisture content to fluctuate more than they would naturally. Nutrients are not replenished as readily as they would be from decomposition.

Mulch, which can be applied at any time of the year, is quite seasonably appropriate in autumn. This is when plants expect decomposing organic matter to arrive from above. Mulch compensates for the loss of what we consider to be a mess, but what plants consider to be an important component to their natural ecology. It gives them what they want, but is neat enough for refined gardens.

The best mulch for the job just might be fallen leaves that were raked last year and composted, perhaps with other debris from the kitchen and garden.

Horridculture – Fake Media

P90911This is no way to get the dirt on someone. There is no dirt involved. If there were, it would be referred to as ‘soil’. ‘Dirt’ is a term used by those who do not know any better.

Anyway, this is about the media that plants are grown in. It might be called growing media, potting media, potting mix or simply potting soil. Some in the horticultural industries might say that, because it is assembled from a variety of components that do not naturally occur together, growing media is synthetic. Because it lacks real soil, most of us refer to it simply as soilless.

Now, I am aware that not all media are created equal. The medium that we grew citrus in was much sandier than what we grew rhododendrons in. It was purchased already mixed specifically for citrus, and ready for use. The medium for the rhododendrons was mixed on site, with more coarsely shredded fir bark (from local mills), less sand and a little bit of perlite.

What I was not aware of, was just how perishable potting media purchased from retail garden centers are. Rather than drive out to the farm for a bin or two of medium, I purchased a bail of common ‘potting soil’ from a garden center about two years ago. I just happened to be there to pick up something else. The cost seemed worth avoiding an extra trip to the farm.

It actually was worth the cost. It did what I needed it to do for a time. The problem I am noticing now is that plants that were not planted or canned up (into larger cans) soon enough are now lacking the volume of medium they need. They need to be stuffed, which involves sliding them out of their cans to add a bit more medium to set them on top of, back in their cans.

The potting soil decomposed too readily. It is as if it rotted into muck that was rinsed through the drainage holes with watering. I suspect that there was more to the medium that the typical simple components. It probably contained significant volumes of compost derived from recycled greenwaste. I certainly have no problem with that. I just would have liked to know about it.

This little American persimmon seedling can stay in this half empty can until winter dormancy. Once dormant, it can be canned into a #5 (5 gallon) can, to resume growth next spring, before it even realizes that it is lacking medium. It will get a happy ending.

To Mulch Is Not Enough

60727thumbMost plants would prefer the real thing; how they do it in the wild. They drop their leaves, flowers and twigs. Deciduous plants do it mostly in autumn. Evergreens might spread it out through the year. The debris accumulates on the ground below, and decomposes at about the same rate as it accumulates. There is no one there to clean it up. Yet, the natural ecosystems know what to do.

The plants that produce the debris use the nutrients produced by its decomposition. So, with the help of the many microorganisms in the soil, they recycle their own trash. To exploit this resource most efficiently, feeder roots tend to congregate near the surface of the soil where the nutrients are. Because the debris also insulates and shades the soil surface, roots are comfortable there.

Densely forested ecosystems produce the most debris. Many smaller plants in such ecosystems may disperse their roots exclusively into decomposing debris without reaching into soil below. In desert ecosystems, where such debris is minimal, roots are mostly dispersed much deeper to avoid the hot and dry soil surface. They wait for recycled nutrients to leach to them through the soil.

Redwoods, cypresses, many pines and most eucalyptus produce unusually thick layers of debris that decompose slowly. This technique inhibits or prevents the germination of seeds of potentially competitive plants. So, in other words, these trees and other plants had this, as well as moisture retention, soil insulation and nutrient recycling, all figured out long before we knew about mulching.

After we put so much work into raking and disposing of foliar debris that would otherwise accumulate in our gardens, it is ironic that we sometimes need to apply seasoned mulch to compensate for the lack of organic material on the surface of the soil. (Unseasoned mulch draws nitrogen from the soil to sustain its own decomposition.) It does more than merely improve the appearance of otherwise exposed soil. Mulch helps unnatural landscape environments function a bit more naturally.

Six on Saturday: Mudslide

 

With all the rain, it was no surprise. Mudslides are somewhat common here, and they sometimes close roads. In fact, we were sort of expecting a small mudslide almost in this particular spot right when we got the call about it. The only slight surprise was that it was right next to where we expected it to be. The cliff that we expected to make this sort of mess was still intact under the tarps put over it to deflect some of the rain.

Fortunately, it was a small mudslide that blocked only one lane. We were able to direct traffic through the other lane while the blocked lane was cleared of debris by a small bulldozer.

The top of the cliff slid to the bottom along with a stump of a Douglas fir that was cut down many years ago. The Douglas fir was cut down so that it would not destabilize the soil that it was rooted into as it moved in the wind. However, The soil was destabilized as the Douglas fir roots that held it together decayed. This is actually a common dilemma, since trees sometimes need to be cut down before they cause such problems, but the death and decay of the roots of such trees ultimately cause the same problems.

The sorts of trees that could be coppiced do not do so well in the dry soil on top of cliffs. Otherwise, we could plants willows, cottonwoods or something of the sort, and cut them down as they get too big, without killing the roots. They would be happy to regenerate and continue the process. The sorts of plants that prevent surface erosion do not do much to stabilize the soil. Otherwise, we could put something as simple as freeway iceplant (Carpobrotus chilensis) on top, and let it cascade downward over the unstable area.

1. It was nothing too serious, but just enough to block the inbound lane. Tarps over the cliff that we expected to make this sort of mess are visible above the retaining wall just beyond. My work pickup in the lower right corner of the picture blocked the inbound lane with its headlights and hazard flashers on. I directed incoming traffic around it into the clear outbound lane as it was available. The young man off in the distance moved his pickup out of the outbound lane, and also directed traffic accordingly. When necessary, he stopped traffic while incoming traffic used the outbound lane. We communicated by radio and hand signals.P90309

2. This is the stump of the Douglas fir that was cut down so that it would not dislodge the soil and cause a mudslide. A decayed stump of a smaller madrone tree is to the right. Their rotting roots and the English ivy were insufficient to stabilize the top of the cliff.P90309+

3. These significant mudstone boulders on the far side of the road could have done some serious damage to a car if one had gotten in their way.P90309++

4. That is where the Douglas fir stump came from, just to the left of the drainage pipe. It did not get very far. That is it at the lower left corner.P90309+++

5. We arrived about ten. By noon, there was not much evidence of what had happened. We left the cones because the road was slippery with mud.P90309++++

6. This is supposed to be a gardening blog, so here is an unidentified fern that witnessed the whole ordeal from a stable portion of the same cliff. There is slightly more flora to this story than two dead stumps and a bit of ivy.P90309+++++

This is the link for Six on Saturday, for anyone else who would like to participate:

https://thepropagatorblog.wordpress.com/2017/09/18/six-on-saturday-a-participant-guide/