Category Archives: soil

Soil Testing & Monterey Bay Master Gardener’s

Master Gardeners rock. I was inspired by the fabulous gardens that I saw on their 2010 Masters Garden Tour and even wrote a column about some of them. Attending the Smart Gardening Fair when it was sponsored by the Monterey Bay Master Gardeners at Skypark in Scotts Valley was always an educational experience. I also read the informative newsletters available on their website. So it was with the same enthusiasm that I attended  the quarterly Monterey Bay Master Gardener meeting earlier this month.

Held at the University of California Cooperative Extension office in Watsonville and open to the public, the meeting lived up the the Master Gardener slogan to "Cultivate Knowledge... by extending research-based horticultural information". The speaker was Cliff Low, owner of Perry Laboratory in Watsonville. If you have ever wondered why your hedge is languishing despite your exquisite care you may need his services.

The lab provides horticultural advising and testing of soil, irrigation water and plant tissue. Cliff works with grape growers in the wine industry, strawberry and cut flower growers and organic farmers as well as home owners and landscape professionals. He can provide fertilizer recommendation for conventional or organic amendments based on soil tests for basic fertility, micronutrients, salinity and alkalinity.

Cliff combines his formal education with real-life solutions and shared some interesting tidbits of his horticultural  knowledge. Grapes, for instance, are prone to zinc and boron deficiencies and may need foliar feeding of these micronutrients. Excess sodium usually only occurs in clay soils. Mediterranean plants thrive in low phosphorus and slightly acidic soils.

I also learned that rose growers for the cut flower industry in this area now use coconut coir as a growing medium. Coir, which is the hair of the coconut shell, is also being used by gardeners as a substitute for peat moss. Although peat moss has natural anti-microbial properties, it is harvested from rapidly depleting peat lands and is not sustainable. Coir has similar properties to peat as a soil amendment and the high potassium chloride in coconuts may guard against garden pests as it does in coconut trees. The down side is the cost of shipping as most coir comes from Sri Lanka, Mexico and the Philippines. Also weed seeds are being imported in with the coir. Still it is the medium of choice for organic farmers.

If you have a well you already know this but it was interesting to me to learn that a well high in iron actually helps plants by providing this element that they need anyway. Slime bacteria that is associated with iron wells, however, is a dangerous health risk and the use of chlorine from household bleach to treat it counters this beneficial affect.

Much can be learned from a soil test provided by Perry Laboratory but If you choose to test your own soil for nitrogen, phosphorus and potassium, be sure your reagent powder is fresh, advised Cliff. Last seasons left over capsules are not reliable. Meters to measure pH are not very accurate either unless the soil sample is uniformly dry. You can contact Perry Lab at (831) 722-7606 or http://perrylaboratory.com

My thanks to Monterey Bay Master Gardeners who offer so much for the home gardener. You can call their hotline (831) 763-8007 for horticultural advice. Their next Master Gardener Training class starts in January 2012. Check out their fall newsletter for articles ranging from integrated plant management techniques for Light Brown apple moth control to the successes and failures this year in members own gardens to how bunny rabbits may be the cause of your plant losses.

 

What to Plant in Clay Soil in the Santa Cruz Mountains

              "The soil is made of butterfly wings, dinosaur teeth, pumpkin seeds, lizard skins, and fallen leaves.
                  Put your hands in the soil and touch yesterday, and all that will be left of tomorrow shall return
                                         so that new life can celebrate this day."  -Betty Peck

Soil is a wonderful thing. It grows our food, anchors our trees and provides a foundation under our feet. But it sure can be hard to work with if it’s not the soft, crumbly loam that many plants prefer. It’s amazing that anything grows in some of the soils here in the Santa Cruz mountains. Some folks garden in an ancient sea bed of sand and there are others who have such heavy clay in their gardens that you wonder how anything survives.  Recently I helped plant in the dense clay of Garrahan Park in Boulder Creek and I dedicate this column to those of you with similar inhospitable soils.

The soil in Boulder Creek required a pick ax to break up enough to plant. Sound familiar?  Although rich in nutrients it needed compost in many areas to provide the environment  necessary so beneficial microbes, worms and other critters could do their work and aerate the soil. A thick layer of mulch will be spread over the soil by The Boy Scouts to preserve the structure and prevent it from packing down again.

There are many plants that are tolerant of clay soils and plant selection is half the equation. The park chose mostly California natives that won’t need fertilization or pruning, can be eventually weaned from irrigation and will provide food for the birds and visiting children. Juncus, a type of grass, red-flowering currant, redtwig dogwood, California rose and western redbud will be the stars of the park in the wet, clay soil. The drier side of the park was planted with deer grass, toyon, California rose, huckleberry, coffeeberry , ceanothus, native honeysuckle, vine maple, native iris and California fescue grass.

I’m sure the park will be the crown jewel of the area and hopefully you will come to visit and see the progress of the plants. Kinda like a local demonstration garden in the San Lorenzo Valley.

There are plants from similar environments in other parts of the world that would also do well if you garden in heavy soil. One of my favorite trees for these conditions is the strawberry tree. Also hackberry, ash, gingko and paperbark trees work well also. Shrubs to try include flowering quince, bottlebrush, Australian fuchsia, smoke tree, escallonia, pineapple guava, mahonia, osmanthus, Italian buckthorn, elderberry and vitex. Easy perennials for clay soils are yarrow, bergenia, carex grasses, fortnight lily, coreopsis, echinacea, nepeta, salvia, teucrium and verbena to name just a few.

If you’re not familiar with some of these plants it’s easy to see what they look like by Googling images. It’s what I do to see a plant full grown and not just a line drawing or a close-up of the flower.

So you see, there are plants that will be successful even in heavy, clay soil, you just have to pick the right ones.

Taking Care of your Soil

Gardening is all about dirt-its care and feeding, its microbes and fungi, bacteria and earthworms. So whether you’re planting your vegetable garden or a border of perennials, feed the soil- not the plants. Start by using organic fertilizers and pesticides. Here’s why.

Most of a plants energy goes to producing substances that it drips out through the roots to attract bacteria and fungi. These in turn attract good nematodes and protozoa to the root zones. To make a long story short, the protozoa eat bacteria and the nematodes eat not only the bacteria but also fungi and other nematodes to get carbon. What they don’t need they expel and this feeds the roots much like earthworm castings.

It gets even more interesting down in the soil. If the plant needs different foods it can change what is secretes. Different substances will attract different bacteria, fungi, nematodes and protozoa. This huge diversity of soil biota helps the good guys keep the bad guys in check.

A common way to destroy the microbiology of the soil is to add salts ( non-organic fertilizers). The salts kill the bacteria and fungi by dehydrating them. Then the plant can’t feed itself and becomes dependent on its fertilizer fix. Without the good bacteria and fungi in the soil other parts of the food chain start dying off as well.

The soil food web is also responsible for soil structure. Bacteria create slime that glue soil particles together. Fungi weave threads to create larger soil particles. Worms distribute bacteria and fungal spores throughout the soil and create pathways for air and water.

What can you do to bring your soil back to life? 

  • Add 1/4" of compost on top
  • Mulch around perennials, shrubs and trees with dried leaves and grass clippings for annuals.
  • Use aerated compost tea
  • Apply mycorrhizal fungi, especially in a new garden that’s been rototilled or chemically fertilized. You can find this in most organic fertilizers and some organic potting soils.
  • Try to avoid walking on the root zone of plants. This kills fungi in the soil. Install stepping stones to preserve soil structure.
  • After employing the above suggestions if you’re looking to add something new to your newly revitalized shady border consider planting a flowering maple that bears lilac blue flowers. Abutilon vitifolium grows to 6-8 ft in partial shade. Gray green maple-like leaves reach 6" or longer. Flowers grow singly or in clusters on long stalks. Abutilons need good drainage.

    As a ground cover underneath them, grow . Vivid periwinkle blue flowers bloom spring through summer. Campanulas are a large family of perennials. Some are low groundcovers like Get Mee’s to 3 ft tall peach leafed campanulas. Both are easy to grow and are choice plants for borders.