There are two primary benefits to crop rotation, and they apply to the smallest of backyard farmers as much as to huge agro-conglomerates.

The first is based on the fact that all plants are prone to certain pest issues. For some it is a specific insect, while others are likely to get fungal infections. To prevent these issues from becoming overwhelming, one of the best tools of smart and chemical-free gardening is to put a given type of plant in a new place every year, as space allows. The idea is that any pest specific to your plant that is living in the soil from last year won't be able to find the plant in its new home. This is a great way to keep blemishes and worms off of root vegetables, minimize leaf miners, and generally keep the pests populations low for any kind of plant.

The second is the fact that each plant needs, depletes, and sometimes adds, a different combination of nutrients from the soil. Some plants, like peas, beans, and clover, will add nitrogen. Others, like carrots, tend to strip nitrogen out of the soil really quickly. As a result, you can accidentally create nutrient-poor zones if you keep planting something in the same spot.


Orderly rows make crop rotations easier

So how does a regular backyard gardener take this into account? The most basic part is simple: Plant each zone with a different plant than last year, and try to do it in an orderly fashion so that you can remember what you did. So, for instance, if you imagine each bullet below is a garden row,

if year one's rows are organized:

• carrots


• peas


• tomatoes


• onion


• potatoes

Then year two should go:

• potatoes


• carrots


• peas


• tomatoes


• onion

And year three:

• onion


• potatoes


• carrots


• peas


• tomatoes

There are some tricks here, like the fact that potatoes and tomatoes are biologically similar, so it helps if you don't make them direct neighbors. And the carrots are always marching behind the peas, which helps with soil nutrition. But really, the most important thing is to keep your plants on the move throughout the years. Even if you just grow two things in a single swath of dirt, switch them from side to side each year.

In another post, I'll delve a tiny bit into plant families, which will help the more adventurous gardeners plan a better crop rotation scheme. For most backyard veggie gardeners, though, just a one-year row shifting scheme as written above will do the trick.

As Mariah mentioned in her recent post, amaryllis are a nearly foolproof way to enjoy vibrant color in the dead of winter - or in my case, in that maddening early-spring period when your plants are just taking TOO LONG to wake up after their winter's nap. In another week or two, these guys - pictured here in early March:



. . . will look like this:



It's not difficult. After you enjoy your blooms, cut the stalks back to about 6 inches, but leave the foliage alone. Continue to water the bulbs and keep them in a sunny spot. When it's quite warm (June) you can bring them outside; I used to plant them in the garden, but now I just bring the whole big pot outside and nestle it among the daylilies that grow like mad on the side of my house. Or you can just leave them on your windowsill, but the leaves do grow to be rather unsightly - they get very long and then buckle into a mess.

When summer is over, bring the bulbs back indoors and repot them. (The dates here are quite loose; last year I forgot about mine until several frosts had passed, and I was sure I had killed them, but they bounced back admirably.)

This next part sounds cruel, but it makes more sense when you understand that the amaryllis grows naturally in the desert. You need to duplicate the desert environment: withhold water, light and heat (though don't let it freeze; an unheated basement is ideal) to allow the bulb to enter the period of dormancy that will allow it to replenish itself and bloom again. I set my pot in a corner of the basement and drape an opaque trash bag over it.

About 6 weeks later (again - very loose dates!) cut off the dead foliage, water thoroughly, and set in a sunny spot. Do not water it again until, several weeks later, you begin to see some wide green shoots poking through the soil. It never fails to amaze me, but they come back with gusto. Every year the bulbs grow larger, and after 3 to 4 years they will divide, giving you an extra bulb to add to your collection. Or, if you're feeling generous, give it to a friend - but don't forget to tell her how to take care ot it!

Some years ago, our species climbed out of the trees and retreated into caves. Personally, I've never gotten over it. I miss living with plants.

Maybe it's a sign that I'm disconnected from the landscape, but I'd love to live in a house covered with plants. A house like that would help me feel part of the natural world, rather than part of technology. After all, the city is technology - it's all about human-built systems, functioning at peak efficiency to replicate those functions formerly performed by the natural world. Don't get me wrong, I'm no luddite. I like technology. But it's not what I'm all about. I'm about leaf litter, and worms, and tomatoes, and all that good stuff.


Photo by Kıvanç, shared via Flickr

I'm not alone in my desire to live among plants. Many people want ivy to grow on their homes. And not just on houses. There's something about plant-covered walls that make large buildings seem inviting, approachable. Architects call this "bringing down the scale of a building." City planners respond to this need by requiring trellises on some buildings, especially on multifamily residences (huge blocks of apartment buildings). Builders respond grudgingly. Check out the pitiful cupful of dirt at the base of the trellis at left. I feel sorry for that plant.


Photo by City of Lynnwood.

When it comes to respecting plants, architects usually don't do much better than builders. They often draw elaborate trellises on their drawings. Then they'll draw some generic plants on their drawings and refer to them disparagingly as "growy things." The plants are an afterthought. Like on the beautiful trellis below: How would a plant even get up there?


Sometimes this is just self-deprecating humor, a nod to the more specialized field of landscape architecture. But it's also a response to the dire warnings of structural engineers, bricklayers, and all kinds of other contractors: Plants destroy houses. Ivy, for example, has little feet that pulls the weatherproof outer surface off walls, exposing the wall's vulnerable interior.


Photo by moplants.com


Photo by Christian Herman, St. Louis Brick

Other plants can damage buildings in other ways Wisteria pulls structures apart. Hedges trap moisture near wood walls, causing them to rot. Roots and vines will seek out a crack, then pry it open as the plant grows. Even my favorite little mountain flower, the saxifrage, comes from the latin meaning "rock breaker."


Saxifrage photo by Brewbooks, shared via Flickr

But some innovative designers are trying to break down that barrier between garden and home. They're using new techniques that allow plants to grow directly on walls, where a highly engineered layer of construction materials protects the wall itself from the plants. Below, the Musee du Quai Branly in Paris, France.


Photo by Markhillary, shared via Flickr

Below, the Millenium Village, U.K.


Photo by Thingermejig, shared via Flickr

In other projects, the plants are held away from the building on a stand-alone metal screen. Below, the Capitol Hill Library in Seattle hopes to be completely covered in vines some day. There are several inches of air circulating between the plants and the brick wall.


Photo by Johnston Architects, Seattle

In some places, you can do it without the building. Check out the "living wall" in the photo below. I don't know how these plants get the minerals they'd normally attain from the soil. But it sure looks cool:


Photo by Thingermejig, shared via Flickr

Growing plants on the roof also helps reduce stormwater runoff and cool down overheated cities. Works equally well on big stores and little garages.


Photo by Mountain Equipment Co-op, Toronto store, shared via Wikipedia


Seattle Architect Rob Harrison's garage

I remember reading an essay by E.B. White from his collection, One Man's Meat. He had recently retired to a small Florida town near the Everglades. He described how, down there, plants thrived in every crack in the sidewalk, consumed buildings on the edge of town. In short, nature would consume this village in a heartbeat. The moment the citizenry put down their machetes, they'd be buried in greenery.


Photo by Eric I. E., shared via Flickr

There's a the old frontiersman's fear of wilderness in that observation. But I think White also admired that wilderness for its tenacity, its fecundity. Personally, I find nature's resiliency comforting. And I don't see any reason to wait for civilization to collapse before we can bring nature into our cities. Really, nature can be quite a polite houseguest. It requires so little of us. Just a crack in the wall.


Photo by Tim Parkinson, shared via Flickr

After following green roof and living wall designs for years, I got a kick out of a recent article in the Seattle Times. Perhaps this is the next frontier:


Photo by Chris Butler, Idaho Statesman

ZRecs.com cover photo by Geishaboy500, shared via Flickr.