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Spring 2023

The ComPost

The Soil Edition

Happy spring, gardeners! As you are replanting your gardens, you are probably thinking about your soil. We are too! In this edition learn the basics about soil amendments, how to use them, and where to get them.


To increase our capacity to provide compost to city residents, we are partnering with SF Environment to hold additional compost distribution events this year. SB1383 requires municipalities to reduce organic waste disposal 75% by 2025 to combat climate change. Organics like food scraps, yard trimmings, paper, and cardboard make up half of what Californians dump in landfills, which subsequently produces significant amounts of methane. Compost produced from these items and applied to green spaces is great for your garden and landscaping and can help California adapt to climate change by sequestering carbon and reducing greenhouse gas emissions.


Our first "compost only" event with SFE will be Saturday, April 15 between 10 a.m. and 1 p.m. in the overflow parking lot at Gleneagles Golf Course. Additional events are being scheduled and will be announced soon. Bring your own buckets, and please, drive slowly through the lot.


For more information about SB1383, read here.

Got a gardening question? We have answers!

In our winter edition of The ComPost we began answering the top 5 questions that are posed to Community Gardens Program staff and volunteers. Here is No. 2 in the series.


Q. What is the difference between soil, compost and mulch? When and how do I use these materials in my yard and garden?

Photo courtesy of Alabama Cooperative Extension System


Soil is not dirt. It is a complex mix of minerals, fungi, bacteria, and other organisms that are living, dead, and decaying. While dirt is something unwanted that we wash away, healthy soil is teeming with life. Building healthy soil means encouraging soil microorganisms that will help plants grow. One teaspoon of healthy soil has more microorganisms than there are people on Earth.


The Ideal garden soil is 40% sand, 40% silt, and 20% clay. If your soil is less than ideal, you can amend it.

  • Too sandy? Add compost, vermiculite or peat.
  • Too much clay? Add fibrous amendments like peat, straw, perlite or wood chips.


We recommend purchasing soil for raised beds and containers from a reputable garden center over finding free soil from a construction site or other location. This will ensure the soil does not contain lead or other toxins. While this can be expensive, it will be the foundation of your garden for years to come.

Photos courtesy of UC ANR


Compost is the product you get when organic material (food scraps, yard waste) decomposes properly. It is a nutrient rich material that is dark and crumbly and used to enrich the soil for better plant growth. Specific types of earthworms can also create a form of compost called castings or vermicompost. Before planting each season, mix two to three inches of fully composted material into the top 6 inches of your garden soil. Compost can improve your soil texture and reduces the need for additional fertilizers.

Note: Organic fertilizers which are produced from living things, (composted manure, feather meal or fish emulsion) help improve the soil where fertilizers made from fossil fuels will reduce the soil's water holding capacity and have other negative impacts on soil health and structure over time.

Photo courtesy of Lyngso Garden Materials.


Mulch is any organic or inorganic material that is spread over the top of soil to suppress weed growth, moderate soil temperature, conserve water, maintain a porous surface, and help prevent soil erosion. Over time, an organic mulch will decompose and help improve your soil. Note, however, that you will still need to add compost because mulch will rob your soil of nitrogen as it breaks down. Both compost and mulch will need to be refreshed regularly. Organic sources of mulch can include wood chips, leaves or straw. The larger the pieces, the longer it will take to decompose. Inorganic mulches can include stones, gravel, and landscape fabric. Choose your mulch based on what you are using it for. For example, straw mulch can be ideal for raised planter beds as it creates a blanket on top of the soil as opposed to mixing in and depleting nitrogen as it breaks down. Wood chip mulch is ideal for pathways and around newly planted trees because it holds in place better.


SF Rec and Park provides free compost and wood chip mulch at our Garden Resource Days. Our next event is Saturday, May 6 from 10 a.m. to 1 p.m. at the overflow parking lot at Gleneagles Golf Course (2100 Sunnydale Avenue). Bring your own buckets and pick up some seeds and plant starts too!

Po(tay)to, Po(tah)to? Let's make chips!!

Photo courtesy of Potatoes USA.

The Agricultural Research Service is Breeding a Better Potato for a Better Potato Chip. YUM!

For decades, one of the top potatoes for making chips has been the Atlantic. But who knew it was a bit fragile, vulnerable to heat necrosis, Hollow Heart, and other sad, sad potato afflictions? We just want them crisp and salty and able to scoop our favorite dips. But given their popularity, (Americans spend more than $7 billion dollars on chips equaling more than 4 pounds per person a year) research geneticists have been working diligently to improve chip potatoes, thank you! The process, however, is a slow one with scientists breeding thousands of crosses every year in search of one that has stronger resistance to disease while maintaining the perfect color, sugar level, storage ability, and several other good spud traits. A new chipping potato, known for now as A13125-3C, is showing potential in national tests. Only when several years of trials and tests are completed will certified seed potatoes be produced and given a name (Can we call it Chip?). While we wait for new and improved chips, we can still enjoy our other favorite ways to eat potatoes: mashed, roasted with garlic, baked with chives and sour cream, scalloped with cream and herbs and of course, French Fries.

The Agricultural Research Service is Breeding a Better Potato for a Better Potato Chip (govdelivery.com)

There are many varieties of potato that will grow well here in San Francisco; they thrive in our cool and humid climate and prefer sandy soil. First early or "new" potatoes should be planted now (late March- early April) for harvesting in June or July, typically requiring 10 - 12 weeks to mature, though our climate may require that all crops need additional time to maturity. Early, or new potatoes, include Yukon Golds or Dark Red Norlands. Second early potatoes can also be started now for harvest in July or August, taking 14 - 16 weeks to mature. Consider Carola or Red Pontiac varieties. And finally, main crop potatoes can be started mid-April and harvested from August to October, requiring 16 to 22 weeks to mature. German Butterball and Canela Russets are good choices here. Purchasing organic seed potatoes, which are certified disease-free, is recommended over planting sprouting potatoes from the grocery store. The seed potatoes can be cut into small segments with each piece having a sprout or "eye". Allow the pieces to dry at room temperature for a few days before planting. Smaller seed potatoes can be planted whole. Plant them just 3 inches deep and at least 6 -12 inches apart to produce larger potatoes. As the potato stem sprouts, mound soil around and over the stems, leaving just the top leaves exposed. Continue to mound the soil as the stems grow, until the mound is 8 inches tall. Potatoes are rhizomatic and will grow on the stems that you have buried under the soil as the plant grows taller. For more information about varieties, when and how to plant, as well as common pest prevention methods, take a look at these resources:


Peirce, Pam (2010). GOLDEN GATE GARDENING: THE COMPLETE GUIDE TO YEAR-ROUND FOOD GARDENING IN THE SAN FRANCISCO BAY AREA AND COASTAL CALIFORNIA. (Copies may be available to borrow from your public library)


UC Master Gardener Program - Potatoes


UC ANR Pest Management Tips - Potatoes

Upcoming Events

If your garden is holding a fun spring/summer event, please let us know (communitygardens@sfgov.org).

Workshops

April


Spring Garden Market and Educational Fair Tired of tasteless tomatoes and other vegetable that just won’t grow in your area? The UC Master Gardeners of San Mateo and San Francisco Counties are holding their Spring Garden Market and Educational Fair in Redwood Hall at the San Mateo County Event Center. Come buy plants for your summer garden: tomatoes, peppers, eggplants, squash, herbs, succulents, pollinators, and more. Varieties have been selected just for the San Francisco and Peninsula climate zones, and grown by local UC Master Gardeners. Plus: free demonstrations and workshops, educational tables and displays, and Master Gardeners available to answer any questions. Most plants are $5 each. Funds raised will be used to support future training and workshops that will be free to the public.

When: Saturday, April 15, 9 a.m. to 1 p.m.

Where: San Mateo County Event Center, 2495 South Delaware Street, Redwood Hall, San Mateo

No registration required. Free admission. Free parking.

Visit the Spring Edibles Plant Library to see what will be available.



Building Healthy Soil Learn how compost can improve the soil in your garden so you can grow vegetables that are stronger and more resistant to disease and pests. This workshop will be led by Master Gardener volunteers from the University of California. Cantonese language interpretation will be provided.

When: Saturday, April 22, 10 - 11:30 a.m.

Where: Brooks Park Community Garden (373 Ramsell Street)

Registration: Please RSVP to communitygardens@sfgov.org.


用堆肥建造健康的土壤 上午 10 - 11:30


了解堆肥如何改善你花园中的土壤,以便你种植的蔬菜强壮且更能抵抗病虫害,这讲习班将由加州大学的园艺大师志愿者领导,将提供广东话翻译,请回复您的花园负责人或电邮communitygarden@sfgov.org


布鲁克斯公园社区花园 (373 拉姆塞尔街)


Perennial Plant Pruning Learn pruning methods that keep your garden shrubs and small trees healthy and looking beautiful. Get hands-on practice, too!

When: Saturday, April 22, 10 a.m. to noon

Where: Garden for the Environment, 1590 7th Avenue

Registration: Pruning Perennials $25 - $50


Ask a Master Gardener This workshop will be led by UC Master Gardener volunteers and will begin with answers to questions posed by garden members and conclude with a tour of garden plots to address individual concerns.

When: Saturday, April 29, 10 a.m. to noon

Where: Maria Manetti Shrem Community Garden in Francisco Park (Bay St. and Larkin)

Registration: Please RSVP to community gardens@sfgov.org


Bouquet Making Learn the craft of bouquet making in this engaging, fun, hands-on workshop, and take your own bouquet home with you!

When: Saturday, April 29, 10 a.m. to noon OR 1-3 p.m.

Where: Garden for the Environment, 1590 7th Avenue

Registration: Morning bouquet or Afternoon Bouquet $25 - $50


May


Growing A Garden: Where to Start Are you really curious about gardening but don't know where to begin? This workshop will teach you the fundamentals so you can get started!

When: Saturday, May 13, 10 a.m. to noon

Where: Garden for the Environment, 1590 7th Avenue

Registration: Growing a Garden $25 - $50


Beginning Beekeeping: The Basics and Mid-Season Colony Health Come learn beekeeping basics, bees' activity in spring and summer, and how to keep a mid-season colony healthy in this engaging workshop!

When: Saturday, May 20, 10 a.m. to noon

Where: Garden for the Environment, 1590 7th Avenue

Registration: Beekeeping $25 - $50


June



Sustainable Gardening Series: Summer 2023 Do you want to learn the basics of sustainable gardening design and care? Join us for this informative, hands-on, three-part series.

When: Saturdays, June 10, 17 and 24, 10 a.m. to noon

Where: Garden for the Environment, 1590 7th Avenue

Registration: Sustainable Series $30



Grow Your Own Food in June In this workshop, learn about managing your vegetable garden during the cool and often foggy San Francisco summer days.

When: Saturday, June 10, 10 a.m. to noon

Where: Garden for the Environment, 1590 7th Avenue

Registration: Grow in June $25 - $50



What to Do in Your Garden Now

April

  • Prune back herbaceous perennials (example: salvia), to promote plant bushiness.
  • Plant edibles like lettuce, tomatoes, herbs, zucchini and berries. Sow bean, corn, cucumber, melon, and winter squash seeds directly into the ground.
  • Transplant tomato seedlings: Pinch off all but the top two pairs of leaves and set the seedling into a deep hole. Backfill, keeping the top leaves above soil.
  • Don’t use insecticides in your garden – you may be harming bees and beneficial insects that actually help control aphids, mites, whiteflies, and other garden pests. For example, Neem will kill other beneficial insects in your garden along with the ones you are trying to remove. Instead, use mechanical controls. Remove aphids from plants with a strong stream of water and handpick snails and slugs, or use non-toxic slug bait.
  • Start planting summer annuals like lobelia, begonia, marigolds, cosmos, petunias, snapdragon and alyssum.
  • Plant gladiolus, dahlias & lilies for summer blooms.

May

  • Plant late summer edibles such as pumpkins, squash, sunflowers, peppers, basil and melons.
  • Prune spring-flowering shrubs after bloom is past.
  • Let self-seeding annuals go to seed instead of deadheading. New seedlings will appear for another crop of summer flowers.
  • Keep your strawberry crop clean by spreading straw mulch around the plants, lifting the flowers and leaves above the mulch. This will also reduce watering needs and cut down on weeds.
  • Harvest radishes when the crown begins to show above the soil. Avoid “split” radishes by going easy on the watering.
  • If you've planted new potatoes, dig them as soon as the plants begin to bloom. Start by gently bringing up the soil with a pitchfork about a foot away from the plant; separate out the tubers by hand.

June

  • This is a good time to plant beans, corn, cucumbers, eggplant, peppers, pumpkins (start now for Halloween), summer squash, and tomatoes. These warm-season plants need lots of irrigation: take this into consideration and plant only as many as you need and can water consistently all summer.
  • Feed tomato plants with a low-nitrogen fertilizer when the fruit starts to develop; too much nitrogen encourages more foliage and less fruit. Mulch the tomato plants to conserve moisture.
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