Building sustainable edible gardens | Portland, OR | Independence Gardens LLC

Ever wondered when to sow seeds indoors so that you’ll have starts available when it’s time to transplant them outdoors? Check out this chart (which we created for 2012, but which is generally fairly accurate year-to-year!).

This is designed to give you a timeline to follow, but remember: plants can and will grow outside of these specific dates, if conditions are right. So, use it as a starting point to develop your judgment about what plants like and when they’re likely to get what they like. And expect the unexpected…within reason!

* For more seed-starting tips and tricks, check out our seed-starting class at SlideShare.net.

‘Tis the season for seed catalogues!

We assume that most people who are checking out our website are Pacific Northwesterners. Probably Oregonians. Perhaps Portlanders. So here’s a list of local, organic, heirloom edible-focused seed catalogues that are suitable for gardeners in our area:

• Botanical Interests
• Ed Hume Seeds (web only)
• Nichols Garden Nursery (web only)
• One Green World [sells plants, not seeds...but we can't resist including this awesome nursery]
• Renee’s Garden (web only)
• Seeds of Change
• Seed Savers Exchange
• Territorial Seed Co.

There are many other quality seed companies out there, and we couldn’t possibly hope to list them all here. If you have a favorite supplier that we haven’t included, let us know.

And if you’re looking for seeds beyond the Northwest, here are a few tips for finding a quality purveyor: try to find a nursery that tests their seeds in your climate, preserves rare varieties, and/or focuses on organic production. Good luck…and enjoy your winter reading!

Lasagna gardening (a.k.a. sheet mulching) is a slow composting method that is used to create and maintain planting areas. It is useful during the growing season for controlling weeds and keeping soil healthy, and it is an especially easy way to transition from lawn to garden during the “off-season.”

You can lay down raw materials for your lasagna garden as you collect them, or stockpile them so that you are ready in the fall to prep new areas for planting the following spring.

Here is how you could turn a lawn into a garden, starting as the summer winds down:

• First, mow short any existing groundcover (e.g. grass).
• Make sure to completely remove any noxious weeds (such as blackberries or bindweed).
• Loosen the soil where you’ll be creating your bed with a broadfork, digging fork, or flat-blade shovel. (This step is optional, because the worms will do a lot of this work for you during the winter!)
• Lay down a weed barrier: 10 sheets of newspaper (not the shiny inserts, just the newsprint part) or thick cardboard (avoid wax-coated corrugated, and remove as much tape and metal as possible). Make sure to overlap the edges at least 6 inches.
• Build up additional materials in 1- to 3-inch layers, alternating “browns” (high-carbon ingredients) & “greens” (high-nitrogen ingredients); 18 inches is a good thickness goal, but don’t panic if you don’t hit it. Some of the many materials that can be used are listed in this blog entry.
• 

  Raised beds can be sheet mulched and capped with straw to winter over.

  Put a cap layer of straw or soil on top to reduce pest attraction and encourage breakdown.

• Wait!

In the spring, you might have to remove a few pieces of compostables that didn’t break down, but you should be ready to prepare a seedbed and plant.

And one last tip: if you are getting rid of grass to make a new garden, make especially sure you don’t leave ANY gaps in the first few layers of the sheet mulch. Grass will find a way to come back.

Composting can be complicated. But it doesn’t have to be!

The first step in setting up a successful compost system (and the only step we’ll cover here) is knowing what you can put in your pile. You might be familiar with some of the no-nos: meat, bones, dairy, fat, and garbage. And you might have heard that you’ll need to use the right ratio of “browns” (high-carbon items) to “greens” (materials that are high in nitrogen).

So, what materials get a “yes”? Which are brown, and which are green? Here’s a short list to get you started:

Material | Brown/Green | Info/Instructions

Yes! Cotton clothing can also be composted. Cut it into small pieces for faster decomposition,

• Fruit & vegetable scraps | Green | Add with dry carbon items to avoid smells
• Coffee grounds & tea leaves | Green | Filters & bags (which are brown) may also be included
• Eggshells | Green(ish) | Best when crushed
• Fresh grass clippings | Green | Add small amounts in thin layers so they don’t mat/clump
• Dry leaves | Brown | Leaves break down faster when shredded or chopped
• Lawn & garden weeds | Green | Only use weeds which have not gone to seed
• Plant trimmings | Green/Brown | Use them fresh for green, or dried for brown
• Straw or hay | Brown | Straw is best; hay (which has seeds) is less ideal
• Fresh comfrey leaves | Green | Excellent compost “activator”
• Pine needles | Brown | Acidic; use in small to moderate amounts
• Flowers, cuttings | Green | Chop up long woody stems (which break down slowly)
• Seaweed and kelp | Green | Rinse first; good source for trace minerals
• Wood ash | Brown | Only use ash from clean materials; sprinkle lightly
• Chicken & other manures | Green | Excellent compost ‘activator’; DO NOT use cat or dog doo
• Shredded (news)paper | Brown | Avoid using glossy paper and colored inks
• Cardboard | Brown | Shred material to avoid matting
• Corn cobs and stalks & sunflower stems | Brown | Slow to decompose; best if chopped up
• Dryer lint | Brown | Use only if the lint is from natural fibers
• Sawdust & wood chips | Brown | High carbon levels; add in layers to avoid clumping

In the Portland metro area, we are lucky. Very lucky, in fact. With the right planning and preparation, we can harvest year-round from our edible gardens. What follow are some of the pieces of information we find most crucial for planning and planting successful fall gardens.

First Frost Date

The #1 factor in planning your fall garden is the first frost date: the first day the temperature drops below freezing, causing damage to frost-tender plants. This date varies in different locations, of course, and some might say it is becoming less predictable overall. However, data collected in past years does allow us to make educated guesses. For instance, the Fall column in the following NCDC chart shows the dates at which there’s a 10%, 50%, and 90% probability that the temperature will drop below 36, 32, and 28 degrees.

According to this chart, it is 10% likely that the temperature will hit 32 degrees (a “light freeze”) by October 24, so it would be reasonable to assume October 24 as your last frost date. More advanced gardeners might want to use the 50% likelihood date (November 15), and push their luck in order to try to get a larger/longer harvest, but the higher the likelihood of hitting freezing, the higher the likelihood that you’ll lose crops to winter damage. The data tables for the rest of Oregon can be downloaded here.

Fall Factor

Not only are gardeners working to try to beat the clock before the last frost date: as fall advances and there are fewer and fewer hours of daylight, plants also grow more slowly! To account for this change, there is a formula to calculate when to plant fall crops.

# of days from seeding/transplanting to harvest (varies by variety—look on seed packet)
+  # of days from seed to transplant size (add only if you grow your own transplants)
+  “Fall Factor” (~2 weeks—accounts for slower growth during cool, short autumn days)
=  # of days to count back from first frost date to planting date

Here’s an example of how to apply the Fall Factor formula to radishes:

28 days from seeding outdoors to harvest
+  0 days from seed to transplant (since radishes are direct-seeded)
+  14 days for “Fall Factor”
=  42 days to count back from first frost date to planting date

Hardiness

Now that you know how to calculate when to plant your fall and winter veggies, you will want to know how much attention they’ll need through the season. You can start to get a good idea of the crops you’ll be able to grow into the fall and harvest through winter by checking out this basic hardiness chart.

As you can see, you can harvest tender, warm-season crops (tomatoes, corn, beans, eggplants, peppers, etc.) up till the first killing frost, then you’ll have to say goodbye and put something else in in their place. On the flip side, you can produce some hardy cool-season crops (kale, turnips, mustard, broccoli, cabbage, collards, Brussels sprouts, Jerusalem artichokes, etc.) well into the fall, while you’ll hold and harvest other hardy and semi-hardy crops (carrots, beets, onions, broccoli, cabbage, etc.) in the garden into the winter.

Crop Protection

As the hardiness chart above shows, at a certain point there are some plants you won’t be able to save. But there are many others that will stick it out in your garden through the winter. However, even the hardiest veggies may appreciate some extra protection as the weather cools and the rain starts falling.

The important thing about protecting your crops is to moderate temperature changes and protect plants from wind and excess moisture, NOT to keep them at summer temps. For your fall and winter garden plants, a little chilly is better than too hot; on a sunny day, the greenhouse effect can rapidly cook your plants! Here are some of the many ways you can protect your fall and winter veggies:

Cloche

A cloche is a mini-greenhouse, usually made with 4 mil or 6 mil plastic clipped over PVC-pipe hoops; if possible, we recommend using pliable (fresh-cut) skinny bamboo instead of PVC, unless your PVC is repurposed! Include vents on the ends of your structure to allow airflow and remove plastic to let rain in on mild days at least every other week.

Cold frame

Cold frames are semi-permanent structures, with glass or plastic on top. You’ll need to leave a cold frame open on sunny days—or better yet, for busy folks, consider investing in automatic openers that will open and close your structure for you as the temperature fluctuates. If it’s really cold, you can insulate your cold frame with straw bales or burlap sacks filled with leaves.

Mulch

Effective protection for established plants can be as simple as straw, leaves, boxes, buckets, milk jugs, pine boughs, or other material on which frost will form first (before it touches your plants). Be creative! Just make sure it minimizes the impact of raindrops falling on your plants, blocks stiff breezes, and doesn’t become a haven for pests.

Experimenting in the fall garden

Finally, it’s worth mentioning our rationale for listing such very basic information in this post, instead of charts of what to plant when. It’s because conditions vary tremendously from season to season (duh!), and also year to year—especially as global weirding progresses. We hope that providing these basic fall gardening concepts will help you figure out what works for you, and then keep improving upon your methods: that is, treat your gardening efforts as an experiment, understanding that results will vary.

Once you understand the basics, if you want to see how we apply this info and receive monthly updates on specific garden tasks, please sign up for our Newsletter.

For additional information on fall gardening, check out OSU Extension‘s Fall and Winter Vegetable Gardening in the Pacific Northwest or Seattle Tilth‘s Maritime Northwest Garden Guide.

It might be worth stating, as a start to this blog entry, that we don’t view any plant as inherently BAD. Nope, not even weeds! Weeds are just plants doing the work they were programmed to do, in conditions favorable to their survival that we’ve either actively encouraged or passively allowed to exist. However, in one way or another, the plants we call “weeds” have work to do that runs counter to our own aims.

In general, we don’t pay too much attention to innocuous weeds that are just there: they don’t bother us much. But there are two very different types of weeds that are worth watching: 1. noxious & invasive weeds, and 2. Good Weeds.

In short, invasives are non-native/introduced species that tend to be aggressive competitors for resources (think takeover weeds); and noxious weeds have a detrimental economic impact and are regulated by federal and state agencies. (Check out the Oregon Noxious Weeds Lists and Pacific Northwest’s Least Wanted List for more information about these naughty guys.) On the other side of the coin, many Good Weeds serve us well: they attract beneficial insects, point to soil characteristics, add nutrients to our gardens, and feed us. So, which ones are which?

Our own current list of most bothersome garden invaders and favorite control strategies includes the following:

Himalayan blackberry (Rubus armeniacus) This picture shows some of our Search and Rescue colleagues plowing through blackberry canes, which we (unfortunately, for many reasons) have to do quite often. To control, we recommend manual removal of canes and rootballs, then mowing—mechanical or biological!—to keep new foliage growth down & exhaust the plant.

English ivy (Hedera helix) This picture is Karen going a little crazy on the ivy-pulling front. For control, we recommend manual removal of foliage and roots; prioritizing cutting down all vines that run vertically (on which growth ivy flowers and fruits) to prevent reproduction; and using goats, when possible, to keep foliage from growing back.

Butterfly bush (Buddleja) The key to buddleja removal is trying to get it before it goes to (prolific) seed. We either do “one cut pruning”—cutting the whole thing off at ground level—and/or cut back the foliage, then do manual stump removal. Also check for seedlings in the area. This is a picture of a stump Isabel  rocked till it popped out. Would that I could post a video–funny!

Field bindweed (Convolvulus arvensis) The pretty flower looks just like morning glory, but we don’t advise ever letting the plant get established enough to flower! At that point, it will be taking over your garden… Do: remove all parts and pieces; lay black plastic over the affected area (this is called solarizing); sheet mulch thickly; and  monitor regularly, especially at edges.

On the other hand, after reflecting on our “favorite” baddies, we’re reminded of the following Good Weeds, which we are loving (albeit still deterring, if they directly compete with our intentional plantings):

Little western bittercress (Cardamine ogliosperma) Yes, this a very clever and successful spreader: it shoots seeds out of seed pods when it is disturbed. And we know gardeners who fight it hard. But you’ve gotta love it, at least a little bit: all young aboveground parts (leaves, flowers, and seed pods) are edible—they are related to & taste like spicy broccoli/mild radish.

Chickweed (Stellaria media) Chickweed is a great salad green…mmm. As with any weed (or, really, any plant at all) that you plan to eat, make sure that your chickweed was harvested from a “clean” location: no dog poop, few passing cars, not in a septic field, etc. Just observe your surroundings and be appropriately cautious, and you, too, can harvest wild dinner!

Plantain (Plantago major) Plantain is a highly adaptable plant, growing broad and narrow leaved versions of itself in rich and poor soils…and cracks in the sidewalk. It is edible fresh (young leaves) and cooked, and is also medicinal. It’s rich in calcium and magnesium; accumulates silicon, sulfur, manganese and iron; & turned under to decompose, it helps deacidify soil.

Red deadnettle (Lamium purpureum) Edible (but not particularly tasty) member of the mint family, the stem tops and leaves are fine to use. It is also attractive to pollinators and other beneficial insects: it blooms in late winter/early spring and attracts wildlife before other plants are in bloom. This is a very good thing!

White clover (Trifolium repens) In addition to mosses, clovers are probably the most widely-viewed-as-annoying spontaneous additions to lawns. But please, please put away the weed and feed! Clovers are often used as cover crops in gardens because they fix nitrogen, and are wonderful soil-builders. Clover is also attractive to beneficial insects and pollinators.

And finally, we love dandelion (Taraxacum officinale): no picture necessary, right? Dandelions are rich in beta carotene, vitamin C and vitamin A; most plant parts (not the puffy seedhead or oozy stem) are edible: a yummy coffee substitute can be made from roots, young leaves are great salad greens, and with the flowers…dandelion tea, or wine! Taproots bring up calcium, iron, and a host of other minerals from the deep soil, and the decomposing roots of dandelions produce humus. Flowering dandelions provide early spring pollen that attracts ladybugs and other beneficial insects to the garden. Almost all soils support dandelions; one that doesn’t is totally unfit for growing things. Eek.

In this season of prevalent lawn care and herbicide commercials, we hope that this short introduction to weeds we love and those we love to hate (well, just a little bit) helps to break down the idea of weeds into something much more complex and wonderful. I’m sure you have a few of your own “favorite” weeds in mind, likely in both the noxious/invasive and friendly/helpful categories. If you’re having trouble with or want to learn more about a weed that is not on our list (of which there are certainly many!), you might check out this great identification resource: Oregon State University Weed ID.

And this is still just the tip of the iceberg. There is yet more to come…

It’s spring! Even as the rain keeps coming down between the sunbreaks, we’re starting to see flowers bloom…garlic stretch to the sky…pea shoots unfurl…and weeds start to get a foothold in our overwintered gardens.

One little dandelion peeking out from behind a watering can

We did the first spring weeding in our garden a few days ago, and sheet mulched a fenceline border over the weekend. This flurry of activity came on the heels of teaching a Garden Soils and Amendments class on Tuesday, during which we identify weed observation as a soil assessment technique. And what’s more, I’ve recently been seeing neighbors harvesting weeds off the traffic medians in our neck of the woods. This combination of weed-related events has made me especially motivated right now to look closely at this remarkable category of plants.

Weeds are a funny garden phenomenon. We define as a weed anything that we don’t think belongs where it is. Can a tomato be a weed? Sure! If it (and, more than likely, a host of fellows) came back from seeds your plant dropped last year, but you really wanted to rotate your tomatoes to a new location…those volunteers can easily be considered weeds. But we tend to label certain plants “weeds” all the time, even if they’re not specifically in the wrong place. If they’re there at all, it is a problem. Or is it?

In a similar vein to the old adage “nature abhors a vacuum,” she also doesn’t take kindly to bare soil. Plants will grow wherever there isn’t anything to compete with. In the edible garden, we have to keep weeds at bay in order to keep the space ready for the bounty of edible-for-us plants that we’re going to have growing…any day now! But is there a way we can respect weeds for what they bring, even as we’re deterring their development?

In my mind, there are four main oft-overlooked beneficial functions that many so-called “weed” plants can serve in our gardens: attracting beneficial insects, giving us clues about soil conditions, adding nutrients to our gardens, and feeding us. Yes, indeed. Mysterious are the ways of the plant world…and weeds anything but just annoying. I’m on a roll, and intend to write about each of these functions in my next few blog entries.

Of course, not every weed is a friend; some of them do deserve that pejorative label. Invasive grasses, for instance, are my own current semi-nemeses…and there are some plants (English Ivy, Himalayan blackberry, and bindweed, for instance) that are in a scary category all their own (on the Noxious Weeds list).

Personally, I don’t really mind the activity of weeding: it’s a great opportunity for sipping a relaxing beverage or talking with a neighbor. But the soils class, the beginning of the weeding season, and watching others productively utilize weed plants has gotten me in the frame of mind to investigate weeds more closely. More to come…