This is the seventh in our biweekly series from Amy Pennington — urban farmer, founder of GoGo Green Garden, and author of Urban Pantry and Apartment Gardening — on how to start growing your own food, no matter how tiny your garden-to-be is.
Today: Amy explains how to become a pro at crop rotations and plant families. For the soil health of your garden, for the productivity of your plants, and for an increased harvest, just plan your garden's year with a few simple principles in mind.
Garden Mapping: Drawing out Plans and Crop Rotations
Now that your beds are prepped, your seeds are started and your soil is being built up, it's time for the best part of urban farming: planting. Before sowing seed and planting small starts in the garden, it's best to have a planting plan. As we discussed in an earlier City Dirt, you should by now have a garden space ready for planting and your garden wish list. Using the wish list and your map, you can begin mapping out and implementing a year-long garden plan. Here are a few key concepts that are helpful to understand before mapping out your beds.
Crops are rotated in gardens (and even in large scale agriculture!) to support healthy soil. By rotating crops through garden beds continually over the seasons and years, you confuse pests, minimize the threat of soil disease, and replenish nitrogen in the soil by planting and tilling in manure. Some crop families must be rotated because they are prone to soil disease -- brassicas (cabbage, kale, broccoli, etc), nightshades (tomatoes, eggplant, potatoes, etc), and alliums (onions, garlic, leeks, etc). And aside from disease, different types of plants use different nutrients. By rotating plant families through the same bed over time, you prevent nutrient depletion in your soil.
From left to right: plant families organized in groups, plantings for spring, and plantings for summer (note the sun's placement)
Crops in the same plant families tend to attract the same pests and diseases. In general, organic gardening follows a crop rotation of "leaf, root, flower, and fruit". Each family takes up a different nutrient and each will help minimize nutrient depletion from the soil:
• "Leaf" family plants (lettuce, chard, kale, etc) draw mostly nitrogen from the soil, to support their leafy green growth.
• "Roots" (beets, carrots, parsnips, radishes, etc) use both nitrogen and potassium.
• "Flower" and "Fruit" plants use mostly phosphorous and some nitrogen. Phosphorous is what allows strong flower and fruit development.
Of course, by planting a mixed bed you further add diversity to the garden, so when starting to map out your beds, keep these plant families in mind.
Position of Your Garden Beds
You must be mindful of the position of your beds and how sun tracks across them. This is important, as sun rises in the east and sets in the west. Depending on where you live, the sun will be strongest at a particular time of day -- plant accordingly to accommodate maximum sun exposure on all plants.
Before and after: planting taller plants on the eastern-most edge of the garden
For example, in Seattle I plant my tallest plants on the eastern-most edge of my beds. As the sun rises and tracks over the bed, these plants will put on growth, in essence blocking anything east of them as the sun sets. Because of this, you don't want to put your tallest plants at the western edge of your bed -- if you did that, they would eventually shade out the rest of it. Make sense? If not, toss a note in the comments.
Additionally, as sun sets there is often shade created on the western-most beds due to the sun ducking behind a neighboring house, a tall fence, a tree line, etc. Considering that the eastern-most beds get the most sunlight, you should place your heat-loving vegetables here too -- plants that need sun to ripen fruit like tomatoes, melons, and peas.
Mapping out Your Garden
Back to the garden wish list! Start separating all of your wish list items into plant families. Typically, I make four columns for Leaf, Root, Flower, and Fruit and list all of the plants under them. When you're through, you'll be able to see where there are missing plants -- often people end up with a LOT of Leaf and Fruit plants. Try your best to distribute evenly so you have variety and don't end up with an entire garden full of greens for the year.
Starting with the plants most near and dear to your heart, map out your beds. Put tomatoes and peppers in one bed, lettuce and kale in another, and so on. After you've placed all of the plants, go back through and designate their sow or transplant dates. This will help you discover if you're able to put something in the beds sooner.
Lettuces and beets planted in a garden bed that will hold tomatoes in June
Here's an example: in Seattle, I transplant tomatoes into the garden on June 1st. This means that I have an open bed space from April through June, about three months. Following the plant family rotation, I should plant a row of beets and lettuces now. This satisfies Leaf and Root, leaving Flower and Fruit (tomatoes) for a June sowing. To fill in a June flower, I would pick Chrysanthemum -- a delicious green and gorgeous flower -- to plant next to the tomatoes. Just like that, I have a natural crop and plant family rotation AND I'm maximizing my beds across two growing seasons.
From here, plan what you'll plant after your tomatoes are harvested in August/September. In September, you can plant another bed full of leafy greens -- kale and arugula do well in fall, or opt for a green cover crop like rye or vetch to replenish soil nutrients.
The first time you map out your garden will be a bit of a brain bender. I know that it reads as confusing now, but this is truly all of the information you'll ever need for successful gardening. If you take two hours this spring to map out your year, you'll never have to think of it again. You just follow the plan and you're golden -- I'm looking forward to all of your comments and questions!
Two examples of garden maps for a season's plantings
Once your map is made, it's time to start planting whether by seed or start. My hunch is you'll have questions on that, so stay tuned for the next edition of City Dirt where we'll discuss just how to sow a seed, a variety of sowing strategies, and when to invest in a plant start instead.
Photos by Della Chen and Amy Pennington