Soil, rather than dirt, is a living ecosystem that supports plant life. When soil is healthy and aerobic, it protects plants from disease, retains and gives access to nutrients, decomposes toxins, and builds soil structure. 

One very important component of healthy soil is organic matter.

Soil scientists teach us that regular additions of organic matter, such as leaf litter, compost, mulch, worm castings, etc., contribute to making the soil that perfect loam that we all wish to attain. Organic matter attracts and feeds the crucial components of the soil food web. As it decomposes, it feeds fungi, bacteria, and nematodes. These in turn feed the next level of microorganisms, and on and on up the food chain. During this feeding frenzy, the byproducts produced are oxygen and essential nutrients that are now accessible by plants. Additionally, good soil structure is created in the process, allowing for air and water migration and then storage, thus allowing better access to the plant's root system.

How can you tell how healthy your soil is?

Look at it. Smell it. Touch it. Are there nice dark chunks of matter that crumble in your hand? Do you see worms? How about other signs of insect activity or tiny bright white feeder roots? Does it smell earthy? These are all signs of soil that's doing well. Conversely, if your soil is a dusty light brown and seems lifeless, or is black and smells putrid, these are definite signs that remediation is in order.

You may choose to have your soil tested to see its specific nutrient structure and amend accordingly. The truth is that by creating a healthy aerobic soil, you can help ensure that your plants get what they need to thrive. As it turns out, Mother Nature knew how to do it all along. 

"Sea of red... mulch, that is" by WSDOT is licensed under CC BY-NC-ND 2.0.

 Benefits of Mulch

Mulch is one of the gardener's most useful tools: applied correctly, it suppresses weeds, improves water retention in soil, and keeps the soil temperature down. But does the kind of mulch matter? And do you tie up nitrogen when you use high carbon materials like wood chips as mulch? 

Color matters

First of all, UC researcher Janet Hartin writes, don't use black dyed wood chips as mulch. Hartin, a resident of Coachella Valley, found that black dyed mulch, along with synthetic lawn and asphalt, can superheat surfaces up to 65 degrees hotter than the surfaces of plants in a study she conducted in the valley over the months May through August. 

To till in or not? 

Second, what about the carbon to nitrogen ratio of your mulch? This becomes an issue when mulch is tilled into the soil. Tilling in high carbon to nitrogen ratio materials like wood chips will tie up nitrogen in the soil leading to stunted plant growth. As the population and activity of the decomposers in the soil increase, they consume carbon and nitrogen, competing directly with garden plants for limited supplies of nitrogen. However, leaving mulch on top to slowly decay over time will not have this effect. 

If you are tilling in your mulch, UC Riverside researchers (Pittenger 584) found that mixing in high nitrogen materials like grass clippings in with high carbon wood chips offset any temporary nitrogen tie up. 

Tilling in green manures like alfalfa straw will supply nitrogen and has been found to be especially valuable to citrus trees. 

Mulch and pests

Other things to consider when mulching are pests. UC Riverside researchers found that voles and gophers preferred trees with mulch. Pill bugs may find a home in leaf litter. Monitor plants and be sure to keep mulch away from stems.      

A few notes on proper application

When applying mulch to trees, be sure to keep the mulch from touching the tree trunk and keep from piling too much on top of the root ball. Roots can grow up into the mulch and girdle the trunk. For other plants, keep mulch 4 to 6 inches away from stems. Apply 2 to 4 inches deep for maximum benefits. 

Work Cited

Pittenger, Dennis R. California Master Gardener Handbook. Edited by Dennis R. Pittenger, University of California Division of Agriculture and Natural Resources, 2015.

Photo by Lynn Young

These jeweled toned beauties are wonderful in the garden.

Nasturtiums are quite easy to grow and usually planted in the Spring after the last frost has passed. I have seen Nasturtiums begin to grow from the previous season as early as January. Many believe they are perennials when in fact, they are annuals. There are so many varieties of Nasturtiums, my favorite being the trailing variety which I love to see climb walls, trellises, and fences. If you are without space, or have minimum garden space, Nasturtiums can be planted in a pot. Hanging pots are great for trailing Nasturtiums. They look amazing when they spill over the edges.

They grow full, flower vibrantly during the spring and early summer with jeweled tone colors, and have bright green leaves reminiscent of lily pads. Butterflies, bees and hummingbirds love this plant.

Nasturtiums grow best from seed sown directly in the soil.  I have also propagated from cuttings that performed well in the garden.

Many gardeners plant Nasturtiums in the garden as a trap crop to draw away aphids from neighboring crops. Try planting Nasturtium next to cucumbers, kale and tomatoes for healthy company and natural pest control.

CARE

Nasturtiums do not need to be fertilized. In fact, fertilizer can produce more leaves than flowers. Developing a good weekly watering system should be sufficient. These beautiful blooms love full sun exposure and show tolerance for shade and some drought, although lack of water will cause flowers to wilt. When it comes to maintenance, trailing varieties can benefit from a light pruning and removal of yellowing leaves. Add the fresh green leaves to salad or enjoy a few pieces prior to discarding.

HARVEST

All parts of the nasturtium plant can be harvested for culinary use. The best time to harvest leaves is when the plant is young - approximately 6 inches tall. Harvest flowers just as they open. You can cut flowers and stems together. Collect the green seed pods when they are just over 1/4" inch in diameter. These can be used for pickling. Discard small, hardened pods.  

Nasturtium seeds for future planting are easy to collect. The plants often self-sow. When they self-sow, the seeds fall to the ground, making collecting a breeze. Seeds will be a mixture of small and mature green and brown pods. I save the green pods for culinary use and collect the brown pods to grow for next season. Discard small, immature seeds, as they do not have a good germination success rate.

How to enjoy your Nasturtiums Leaves, Flowers and Seed Pods

All parts of Nasturtium plants are edible. The leaves, flowers and green seeds are used in cooking. The spicy leaves and flowers can be used fresh in salads. The green seed pods, which have a zesty tangy peppery flavor, have become known as “Poor Man's Capers.” I enjoy them fresh. There are so many culinary uses for fresh or pickled parts of the nasturtium plant. I have shared a use below.

Nasturtium Pickled Capers: 1-1-1

1 Cup of firm green seed pods

1 Cup of White Vinegar or Apple Cider

1 teaspoon of Sea Salt

8 Peppercorns

*Add a drizzle of honey for a sweet & tangy taste. Alllow the mixture to sit for 20 minutes or longer. Enjoy. Refrigerate whatever is left! 

Photos by Sabrina Williams

Soil is...

not dirt, of course. Many of us who have spent time in the garden know that dirt is essentially dead. Soil, on the other hand, is a living, complex ecosystem. As one of a triumvirate of life-giving elements — the other two being sun and rain — it has the power to sustain agricultural productivity and protect environmental resources. When you look at it up close, the world within it is reason enough to be impressed. In one cup of soil there are upwards of 200 billion bacteria, 20 million protozoa, 100,000 nematodes, and 100,000 meters of fungal hyphae! Sadly, human activity has contributed to the degradation of soil ecosystems, and consequently, a warmer, dirtier planet. 

Soil Health Is…

also referred to as soil quality, and is defined as the continued capacity of soil to function as a vital living ecosystem that sustains plants, animals, and humans. According to the Soil Health Institute, a healthy soil provides many functions that support plant growth, including nutrient cycling, biological control of plant pests, and regulation of water and air supply.

Assessing how well soil performs its functions in the present, and its ability to do so in the future, can't be determined by any single result. Assessment relies upon many indicators.  A “short” list offered by the folks at the USDA Natural Resources Conservation Service includes soil organic matter, soil structure, soil depth, water holding, habitat for soil microbes, tilth, reactive carbon, soil nitrate, soil pH, phosphorus and potassium, plant and microbial activity, earthworms, soil respiration, and total organic carbon.

Prioritizing Healthy Soil Is…

the best way to create resilient ecosystems. In doing so, we can reduce global food insecurity and environmental impacts of greenhouse gases. There is a lot of talk about CO2 (carbon dioxide) and its contribution to greenhouse gases. A powerful way to reduce CO2 in the atmosphere is to sequester it in our soils. Plants naturally help remove it through photosynthesis and sending the balance to the soil. So, not only does soil do the yeoman's work of retaining water and nutrients, but incredibly, it also sequesters carbon in excess of that retained by the sum of all plants and the atmosphere! 

Importantly, healthy soil also feeds the world. It helps the 500-million smallholder farms globally who produce 80% of the world's food. According to the World Resources Institute, these farms will not be able to produce enough food for over 9 billion people without dramatic changes in how food is produced, including focuses on soil health and water management.

We are…

all stewards of the soil. The benefits of healthy soil don't just accrue to the small farms described above. Home gardens worldwide also can combat soil-depleting practices through crop diversity, proper fertilization, and no-till gardening. And, as more households in urban areas grow more at our homes, yards and urban gardens, we are altogether more productive per unit of area than are large producers. 

We aren't often presented clear opportunities to have a hand in averting a point-of-no-return climate crisis. As growers, soil is…ours.