Category Archives: edibles

Growing Cover Crops- Part I

Every drop of rain that hits bare soil is destructive. Over 3000 years ago the Chinese knew how to protect their soil from erosion and increase fertility by planting cover crops. Early Nile Valley inhabitants 3500 years ago also practiced this method of agriculture as did first century Romans. Lupines were planted in poor soil when no animal manure was to be had. I learned this and also how to protect and improve my soil from Orin Martin, manager of the Alan Chadwick Garden at a cover crop workshop recently on the campus.

aster_Michaelmas_daisy.2048“It’s all about the biology of the soil”, Martin said. “You grow the soil that helps you grow the plants”. A cover crop is really anything that covers the soil and protects it from rain, trapping nutrients and preventing them from leaching downward, he explained. Cover crops can increase the tilth of the soil. Quick germinating grasses easily loosen the top foot of soil with their root mass. Legumes have a tap root, a bio drill, that penetrates 30″ downward while alfalfa roots can grow even deeper.

Cover crops like bell beans, vetch and fava beans are especially valuable as they increase nitrogen levels in the soil in two ways. Atmospheric nitrogen can be “fixed” and left in the soil to fertilize subsequent crops. This is in addition to the nitrogen left from the foliage of the legume.

Cover crops are also called green manure when they are chopped up and turned into the soil in spring lettuces_after_cover_cropping.1024before going to seed. The planting of legumes like peas and beans can actually increase nutrients in your soil giving you a net gain which is needed to offset what you take out of the soil when you harvest fruits, vegetables and flowers.

From late September to the end of November is the best time to sow cover crops. You will need to irrigate lightly a couple times per week if it doesn’t rain. You can also wait to sow just before the rains start. Be careful about working overly wet soil however as you can ruin the structure of your soil.

The Chadwick Garden, Martin explained, originally was heavy red clay. 35 years of soil building with bell beans and vetch cover crops and compost have established a level of fertility that now supports several acres of vegetables, fruit trees, berries and beneficial flowering plants. Fall-sown, spring ploughed-down cover crops are the sole fertilizer used for the better part of the last decade.

Soil_builder_cover_crop_mix.1600Martin explained that recent research now recommends planting a tandem of grasses and legumes. Annual cereal grasses such as oats, rye and barley germinated quickly to hold and shield the soil until the legumes take hold. Bell beans, fava beans and vetch which are the best legumes for our area grow slowly the first 3 months then take off growing 70-80% in the last 3 months. The ratio of grass seed to legumes can vary from 10% to 30%.

There are other legumes that fix nitrogen but no where near as efficiently as bell beans.  Crimson clover seed is also more expensive, needs lots of water to sprout and competes poorly with weeds. Mustard causes competition with the fruit trees as bees will concentrate on the mustard flowers instead of the fruit tree flowers.

A question came up about using inoculants on legume seed. Martin explained that our soils have a native resident population of good bacteria that will break down the seed coat and encourage the plant roots to fix more nitrogen especially after cover cropping for a few years.

We all followed Martin out to the cover crop trial plots to see how the different types were growing. Bark chips will soon be applied to the paths. All of the gardens are mulched several times per year with wood chips. A 10 year study, Martin explained, demonstrated the amazing benefits of ramial chipped wood which is the type the tree service companies provide for free.

We watched him work the soil lightly with a metal bow rake then broadcast 8-10 seeds per square foot. Weeds were already cleared but Martin said this step doesn’t have to be perfect. Afterward the area was raked again lightly 1-2″ down and covered with 3-4″ of straw. Wood chips would be fine, too. Mulch heavier if you have bird competition. Cover crops are vigorous and will come up through just about anything, he said.  Water in lightly.

There are 3 ways to fertilize, Martin said. You can buy chemical fertilizer which is expensive and doesn’t do much for the soil. You can apply compost, which being carbon based, ramps up beneficial fungal organisms in the soil. Or you can cover crop or grow green manure which increases beneficial soil bacteria. Orin Martin has proof of the benefits of the last two methods.

What to do in the Garden in September

I never want summer to end. Who doesn't love those long days and warm nights? The calendar might say fall is near but Indian summer is one of the our best seasons so I love this time of year, too. But then I get all excited when spring rolls around and everything is in bloom. It's all good. I have a check list of some garden tasks  I need to do at this time of year so I better get to them between hiking and trips to the beach.

Fertilize shrubs lightly one last time if you haven't already done so last month. All shrubs, especially broad-leaved evergrimperata_cylindrica_rubrum2eens such as rhododendron, pieris, camellia, hebe, need to calm down, stop growing and harden off to get ready for the winter cold. Some plants have already set next year's buds.

Roses especially appreciate a bit of fertilizer now, encouraging them to bloom another round in October. To keep them blooming make a habit of pinching and pruning off old flowers. Always cut back to an outward facing branchlet with five leaves. There are hormones there that will cause a new rose to grow much sooner than if you cut to one with only three leaves. You can always cut lower on the stem if you need to control height.

Deadhead flowering annuals and perennials in the ground as often as you possibly can. Annuals like zinnias and cosmos will stop blooming if you allow them to go to seed. The same is true of repeat blooming perennials like dahlia, scabiosa, echinacea and lantana. Santa Barbara daisies will bloom late into winter if cut back now.

These plants know they're on this earth to reproduce. If they get a chance to set seed the show's over, they've raised their family. Try to remove fading flowers regularly and you'll be amply rewarded. If you want to start libertiaperennial flowers from seeds this is the time so that they'll  be mature enough to bloom next year.

Now through October, divide summer blooming perennials like agapanthus, coreopsis, daylilies and penstemons that are overgrown and not flowering well.  You can also divide spring blooming perennials like candytuft, columbine, astilbe, bergenia and bleeding heart but sometimes they don't bloom the first spring afterwards due to the energy they use re-establishing themselves.  If you're on  a roll out in the garden, though, go for it now.

It's still a little hot to plant cool season veggies starts in the ground. They appreciate conditions later in September when the soil is still warm but temps have cooled. It is OK to plant seeds of beets, carrots, spinach, arugula, mustard, leeks, onions, peas, radishes and turnips.

If you aren't going to grow vegetables in the garden this fall consider planting a cover crop like crimson clover after you've harvested your summer vegetables.  Next month I'll talk about how to go about doing this and how this benefits your soil.

Cut back berries vines that have produced fruit.  Canes of the current season should be trained in their place.

OLYMPUS DIGITAL CAMERASpider mites are especially prolific during hot, dry weather.  Sometimes you don't even know how bad the infestation is until all your leaves are pale with stippling.  Periodically rinse dust and dirt off leaves with water.  Spray the undersides of infected leaves with organics like insecticidal soap switching to neem oil if they build up a resistance to one of the pesticides. 

Now that you've taken care of your chores reward yourself by  to your garden for color in late summer through fall. Take a look at the garden areas that aren't working for you and replant. Good choices include aster, chrysanthemum, coreopsis, and gaillardia. Abutilon also called Flowering Maple come in so many colors that you probably need another one in your garden.  Petite Pink gaura looks fabulous planted near the burgundy foliage of a loropetalum. Don't overlook the color of other foliage plants like Orange Libertia and Japanese bloodgrass in the garden.

One last to do:  Make a journal entry celebrating the best things about your garden this year. 
 

Beneficial Gardens in a Small Space

waterfall_2He told me that his was a one-of-a-kind garden, unique in such a small space and would I be interested in visiting some time? I love being invited to tour all types of gardens but I had an inkling that the garden of Rich Merrill, former Director of the Horticulture Dept. and Professor Emeritus at Cabrillo College, would be something special.

It was a beautiful morning when I arrived at Merrill's garden overflowing with flowering plants, small trees, edibles and water features. Many large boulders, surrounded by pebbles, caught my attention in such a small space. All part of the design to attract beneficial insects I was told. His organic garden is teeming with small beetles, spiders, predatory bugs, syrphid flies, parasitic wasps and lacewings. It's the ideal method of pest control, environmentally safe and free of cost.

While admiring his lovely garden, Merrill shared his knowledge of beneficials- from insects to birds to spiders to frogs and beetles. They are all part of the ecology of a successful habitat garden. I could barely keep up, writing down notes on my yellow legal pad as he weaved a story about how each of the elements in his garden contributes to its total health. I was never able to take one of his classes at Cabrillo College so this was a real treat. My own private class.

The wide diversity of plants in Merrill's garden provide moisture, shelter, prey and nutrition in the form of santivalia2nectar for carbohydrates and pollen for protein. His plants are "beneficial" plants because they foster beneficial insects. It just so happens  that many of these plants are also beautiful in the garden. Some of his favorites include composite flowers like sunflowers, marigolds buckwheat, scabiosa and santivalia or creeping zinnia.  They have flat  flower clusters with accessible landing platforms and small nectar and pollen to make it easier for insects to feed. They in turn eat the tiny eggs of the bad bugs in your garden. His is a complete ecosystem.

This 800 square foot garden happens to be in a mobile home park but any small space could be designed to be as beautiful and full of life as Merrill's. Most of my clients ask for a garden filled with color, hummingbirds, songbirds, butterflies and wildlife so I came away with lots of great ideas.

blue_thunbergia2Once a teacher, always a teacher. Merrill gave me a handout he'd prepared for Renee Shepherd of Renee's Garden, explaining in more detail why he lets the broccoli go to flower to attract beneficials and why he allows aphids on his cruciferous vegetables to feed the beneficial insects when prey is scarce so they are on hand should he have an outbreak of bad insects that might ruin his flowers and plants.

As we strolled within a border of palms, olive trees, phormium, bottlebrush, Marjorie Channon pittosporum and cordyline, Merrill showed me his philosophy of right plant in the right place in action. Asclepias curassavica, commonly called Mexican Butterfly Weed, has self sown on its own in unexpected spots. One happened to come up next to the gorgeous blue thunbergia by the pondless waterfall making an awesome combination. Both monarch butterflies and hummingbirds enjoy the nectar.

Next to a red salvia, a red and white bicolor Rose of Sharon made it's home. Merrill lets all his plants intertwine and the pink flowering Heckrottii honeysuckle was already inching up into an olive tree. Other salvias in his garden include Hot Lips, San Antonio and San Jacinto. There isn't room to grow any of the larger salvias, Merrill explained. He swears he doesn't know where the brilliant blue one came from. Must be from the "fairy dust" his wife, Dida says he sprinkled over the garden to make everything grow so lush.

She loves flowers for fragrance and cutting so in several beds they grow gardenia, lemons, roses and alstroemeria among the alyssum which is a prime syrphid fly attractor. Several bird of paradise, obtained from different locales in the hopes one will be hardier grow beneath a tall palm.

Merrill grows only the vegetables that do well and are the most nutritious like kale, onions, garlic, broccoli and collards. He enjoyed growing cucumbers this year and has a large pumpkin in the making for his grandson. The rest he gets from the farmer's market. He had developed his own strain of elephant garlic which is actually a leek and has a milder flavor than garlic. I left his garden with a gift of elephant garlic and lots of inspiration.