Blog module icon

MMWD Blog: Think Blue Marin

Welcome to our blog! Written by staff at MMWD, “Think Blue Marin” explores all things water in south and central Marin—water supplies, conservation, new projects, watershed management, and more.

Need Help?
For tips on subscribing, searching, and commenting, please visit our blog FAQ page.

Apr 21


Posted on April 21, 2017 at 9:17 AM by Ann Vallee

by Charlene Burgi

sheet mulching benefits
Top to bottom: 1) Weedy area in need of sheet mulching. 2) Mulched bed ready for spring flowers. 3) Last summer’s vegetable garden—sheet mulched and weed-free
For years I have championed the benefits of mulching and specifically sheet mulching. This year is no different, except for the knowledge of what will occur due to the vast quantity of rain we've experienced this past winter. 

Let's face it: This year weeds are going to be a particular challenge. The wet weather coupled with the occasional warm, sunny days are just enough to cause weed seeds to germinate at an alarming rate. Follow those sunny days with healthy doses of storms acting as irrigation, and we are all looking at bumper crops of weeds. As much as I hate to say it, it’s the perfect storm for weeds. 

There are numerous ways to deal with this unwanted vegetation, but sheet mulching is weed suppression at its best. It is environmentally friendly, builds healthy soil, and is simple and inexpensive. See our step-by-step guide

With sheet mulching, there’s no need to clear weeds first. You can sheet mulch right over the top of them—or even over the top of an unwanted lawn. Overlapping rolls of cardboard or flattened boxes prevent weed seeds from germinating. By eliminating light, the cardboard also kills existing plants by depriving them of the energy needed for photosynthesis. Eventually, the decayed plants will add nutrients to the soil as they are cycled back into the earth. 

When sheet mulching, I always add a two- to three-inch layer of organic material such as bark or straw on the top of the cardboard. The organic material will also break down in time and aid in building healthy soil. When the cardboard and bark have broken down, simply add another layer of each on top. You will be amazed at the rich soil you can build through this process.

What attracts me even more to this method of achieving healthy soil is the ease of weeding in areas that have been sheet mulched. Any weeds that manage to find their way into these areas are easy to pull out. 

My flower beds this spring are a prime example of the labor-saving benefits of sheet mulching. One flower bed has a healthy layer of bark and few weeds. On the other hand, exposed soil in the flower bed to the south is sporting weeds about eight inches high at the moment. I never mulched that area, as the plants went into containers that sat in that space. The price for my lack of forethought will be the extra effort needed to tidy up the area this year. 

Tomorrow I’ll break down the cardboard boxes I’ve been saving to sheet mulch that area. Bark will complete the project, and the health of the garden will be restored in all of those beds with the promise that next year won't be as labor intensive. Already this year will be a lot less effort than if I tried to pull all those weeds by hand. With Earth Day coming up this weekend, sheet mulching seems like the right way to celebrate!

Apr 14


Posted on April 14, 2017 at 11:39 AM by Ann Vallee

by Charlene Burgi

asparagus ready for harvest
 Asparagus ready for harvest
A recent walk through my garden revealed peach-tree blossoms promising an abundant crop to come. And there in the shade of the peach tree I spotted another harbinger of spring: the tips of asparagus heads randomly pushing up through the soil. There were fat ones, skinny ones, green ones and purple ones. There seemed to be no order to where they were popping up—certainly they were not in the neat rows where I had planted them. However, at least I knew the reason for the various shapes and colors.

Asparagus come in an assortment of varieties. In Marin I was most familiar with the Martha Washington asparagus that we sold at our nursery during bareroot season. After investigating more about this perennial vegetable, I learned the Martha Washington produces both male and female plants. The females produce berries on the fern-like foliage and are not as productive as the male plants. Further investigation found other asparagus varieties that are all male, including the Jersey series—Jersey Giant, Jersey Knight and the Jersey King. Being the plant geek that I am, I planted all of them including the Martha Washingtons in a raised planter box. The outcome was a variation of colors, sizes and succession crops. What a treat! Without realizing it, I have prolonged the availability of this delicious vegetable in my garden.

Asparagus are unique plants that require unique planting techniques, as well as some patience. After planting it takes up to three years to allow the root system to mature for harvesting. Long before that step comes the preparation. I knew the asparagus would require their own space as they will take over the garden if left free to spread out, so I selected one of the raised beds in which to confine them. Next, I filled the bed with rich, well-draining soil mixed with compost. I tested the acidity of the soil and adjusted the pH to approximately seven. (A soil tester can provide pH information.) I dug the trenches 12 inches deep and two feet apart, then set the root crowns 18 inches apart in the trenches and covered with two inches of prepared soil/compost mix. 

As the new growth appeared, I covered the asparagus with an additional two inches of soil. I repeated this process until the trenches were filled, watering the crowns after each phase of backfilling. Finally, the filled bed was covered with a layer of mulch to retain the moisture, and the crowns were allowed to mature a year or two before harvesting. 

Each spring, I fertilize the soil with organic products such as bone meal, blood or fish. In the fall, I cut the fern-like foliage down to about three inches and cover the bed with well-rotted chicken manure shavings saved from the henhouse. 

There is so much information out there about asparagus including its history, recipes, growing conditions and varieties. My research unveiled this website that has more information than most people would care to know about asparagus. But for the plant geeks out there, enjoy!

Apr 07

Succession Planning

Posted on April 7, 2017 at 2:56 PM by Ann Vallee

by Charlene Burgi

Spring daffodils
 Spring daffodils
A few weeks ago, the tête-à-tête daffodils popped up in my front yard to display their dwarf, yellow, trumpet-like blooms. Their appearance delighted the eye after a long dreary winter. Not far behind their nodding flowers came more spikes of more daffodils of various colors yet-to-come. I have planted these harbingers of spring over the course of many years, knowing the different types of daffodils will bloom at various times in the spring, prolonging the bright cheeriness. The appearance of the tête-à-têtes foretold that the show was just beginning.

Extending the season via succession planting isn’t limited to daffodils. Spring is in the air and many of us are itching to get into the vegetable garden with the thought of fresh, home-grown produce. Often we plant out the entire area at once, leaving little room for additional plants. This can result in an overwhelming crop coming in all at one time. Then these plants exhaust their production and the fruiting stops.

Careful planning can eliminate this feast or famine cycle. Succession planting, such as planting in monthly intervals, helps provide a manageable harvest of just the right amount of veggies for your family—thereby eliminating the need to set up a fruit and vegetable stand on the front sidewalk.

Some crops are better suited to succession planting than others. For example, beets, corn, green beans, peas, radishes, carrots and lettuce are a few vegetables that do well by monthly planting. Note that if you plant your seeds by the phases of the moon, underground crops such as beets and carrots will do better if planted during the waning phase before the new moon. This can require additional thought and planning. Sometimes it helps to set up a chart or calendar as a reminder of what needs to go into the ground when.

Strawberries are another consideration in regard to succession planting. Strawberries are perennials and don't need to be torn out once they have finished fruiting. The June-bearing strawberry provides fruit in abundance for three weeks during—you guessed it—June. They are a feast or famine crop but just the thing if you make jams or preserves. However, some strawberries are everbearing (otherwise known as day-neutral) and bear fruit from July through fall. Their crop production is spaced out over the months and works well for an ongoing edible harvest. Planting both types of strawberries extends the harvest time a month. Strawberries thrive on an acidic fertilizer.

Plan ahead and your garden will be a source of joy and highly prized for its balance.