With some vegetables, the depth of a container is as important — if not more important — as its width. You can grow quite a few carrots or radishes in a narrow container, but the container must be deep enough to accommodate the length of the plant's mature roots. See the section "Knowing Which Vegetables Grow Well in Pots," later in this chapter, for more on size issues for specific vegetables.
A half whiskey or wine barrel is a large, inexpensive container that can hold quite a few vegetables — ten heads of lettuce, ten bush bean plants, one or two small tomato plants, or four or five small cucumber varieties. You can purchase these containers at garden centers and nurseries.
Material: What a pot is made of can affect how often you have to water and how long the container lasts. Pots made of porous materials like clay dry out faster than those made of plastic or wood, so you must water the plants in them more frequently, especially in hot or windy climates.
If you want to use wood containers, make sure they're made of rot-resistant materials like cedar or redwood; otherwise, they won't last very long. I prefer not to use preservative-treated wood containers for growing vegetables or other edibles, because the chemicals may leach into the soil and then into my plants. If my redwood or cedar pots eventually rot after 10 years, I just replace them — the same goes for my half whiskey barrels.
Drainage: All the pots you use for growing vegetables should have drainage holes; fortunately, almost all do. But because a wooden half barrel often doesn't, you have to drill your own holes in the bottom of the container (eight to ten evenly spaced, 1-inch holes should be fine). If pots don't have drainage holes, the soil becomes a swampy mess, the roots drown, and the plants die. Bummer.
You need to consider two other accessories when you shop for pots:
A saucer to place underneath your pot: A saucer collects water that runs out of the holes in the bottom of a pot and prevents the pot from staining whatever it's sitting on. You can find saucers made of the same or similar material as your pot or ones made of clear plastic. Plastic saucers are least likely to stain.
Just make sure you don't let water stand more than a day in the saucer; water rots roots and wooden pots.
Wheels for mobility: Most nurseries sell wheeled platforms that you place under large pots to move them easily. Otherwise, you have to lift the heavy pots or cart them around on a hand truck.
An especially useful type of pot is a self-watering container (see Figure 18-1). This type of pot is made of rubberized plastic and has a false bottom and reservoir under the soil that can be filled with water. You pour water into a pipe at the top of the pot or through a hole in the side of the pot to fill the reservoir. The water naturally wicks up from the reservoir and into the dry soil so you don't have to water as frequently. These pots allow you to get away during the heat of summer and not worry whether your plants are getting watered.
Figure 18-1: A self-watering container.
Filling Up Your Container: Potting Soil Made Simple
Don't fill your pot with soil from your garden — even if your garden has the very best soil on the planet. It's too heavy and too dirty (you know, weed seeds, bugs, bacteria — stuff that you don't want in your pots), and it may not drain properly in a pot.
Instead, use potting soil. I can tell you a lot about potting soil: how it's well aerated, sterile, lightweight, and made of a good balance of organic material and mineral particles like sand or perlite. I can even give you a recipe to make your own, but you'd nod off in a second. So just trust me on this one.
At your local nursery or garden center, buy a packaged, sterilized, soilless potting soil that's meant for container growing. If you need a large quantity, many nurseries sell potting soil in bulk. You may want to try different brands over time to see which ones are easiest to wet and which ones have the best moisture-holding capacity and drainage. But don't have a personal crisis over which brand of potting soil you buy; caring for your vegetables properly after you plant is more important than choosing the perfect potting soil.
If you're growing vegetables in large containers, you'll be shocked at how much potting soil you need to fill each container. However, you don't have to fill the whole container with soil. Most vegetable roots only penetrate 10 to 12 inches into the soil. Add more than that and you're simply wasting soil. A trick to use less soil is to put empty plastic soda and milk bottles in the bottom third of the container, and then throw the soil on top. The container will be lighter and easier to move, you'll be recycling to help the environment, and you won't have to buy as much soil. Talk about a win-win-win situation!
Don't use the same soil each year; it may have unwelcome diseases and insects in it. It's best to start fresh by replacing the potting soil in your containers each year.
Knowing Which Vegetables Grow Well in Pots
If you're persistent, you can grow any vegetable in a pot. However, some of the bigger plants, like squash and watermelon, are pretty tricky to contain and tend to get unruly. But don't worry, many other vegetables fit perfectly in pots. In the following sections, I describe popular container veggies you can begin with and provide some of my favorite veggie combinations.
Some common container veggies
Vegetable breeders have long had container gardeners in mind. They breed many small-space varieties (of even the most sprawling plants) that are ideal for growing in pots. So in the following list, I take a look at the most common vegetables to grow in containers. (For more information on varieties, see Part II.) If you can't find the dwarf varieties that I mention here, try anything with the words compact, bush, baby, midget, dwarf, tiny, or teeny in the name:
Beans: Bush varieties like ‘Provider' and ‘Derby' are best; you can grow three to four plants in a 12-inch pot. You can grow pole types in a long narrow box, but you have to attach some type of trellis (see Chapter 15 for more on trellising).
Beets: Any variety grows well in a pot, and smaller varieties like ‘Red Ace' even grow well in smaller pots. However, make sure your pot is big and deep enough (at least 12 inches); beets don't like to be crowded. You should end up having about six plants in a 12-inch pot — more if you're growing them for greens or will pick them as baby beets.
Carrots: Carrots are a perfect vegetable to grow in a pot. Start with baby varieties like ‘Little Fingers', ‘Short 'n Sweet', or ‘Thumbelina'. If you water diligently, you can get a bumper harvest in pots as shallow as 6 to 8 inches deep. Longer varieties need deeper pots. After thinning, you should end up with 20 or so carrots per 12-inch pot.
Cole crops — broccoli, cabbage, cauliflower, and so on: All the cole crops grow well in containers as long as your pots are big enough; try planting three or four plants in a half barrel.
Cucumbers: You can't go wrong growing small cucumber types like ‘Bush Pickle' and ‘Salad Bush'. I've harvested cucumbers out of 12-inch-diameter hanging pots — planted with three seeds to a pot. Plants dangling over the edges of a hanging pot are something to behold. Plant large-growing varieties in bigger pots and slip a sturdy wire cylinder into the outside edge of the pot for the plants to climb on.
Eggplant: An eggplant's purple foliage and compact habit are perfect for pots; any variety works as long the container is at least 5 gallons. Plant one eggplant per 5-gallon pot. If a plant gets floppy, push a small stake in the pot to support the plant.
Lettuce and other greens: Lettuce and greens may be the ultimate container vegetables. The size of your pot doesn't really matter — just sprinkle some seeds in it, keep the soil moist, and then get out your salad bowl for a great harvest. You can harvest the whole plant or snip off just what you need. If you want a really pretty pot, plant some ‘Bright Lights' Swiss chard.
Melons: Melons aren't ideal container subjects; they're wild and unruly. But through the magic of modern science, some dwarf varieties, like ‘Bush Sugar Baby' watermelon, grow well in containers. Plant one to two plants in a big pot (at least 5 gallons) and let the vines sprawl over the edges, supporting th
e fruit if necessary. And don't let up on water and fertilizer.
Onions: Green onions — scallions or bunching onions if you prefer to call them that — grow well in containers. Just buy a bag of sets, plant them 2- to 3-inches deep, and you're in business. You can grow onions to full bulb size; just make sure that you use a big pot (preferably 5 gallons) and give them plenty of room to grow.
Peas: Go with dwarf pea varieties like ‘Green Arrow' and ‘Maestro', English peas, ‘Sugar Bon' snap pea, or ‘Dwarf Grey Sugar' snow pea. Any variety larger than that needs a trellis. Planting six plants in a 12-inch pot should be fine.
Peppers: You can grow any pepper variety in a pot, but the bigger the pot the better. I like to grow small-fruited varieties like ‘Serrano' and ‘Black Pearl' peppers; they produce so much colorful fruit that their containers become showpieces. A 5-gallon pot should hold one to two plants.
Potatoes: Potatoes are fun vegetables to grow in a container. Just place 8 to 10 inches of potting soil in a big pot (at least a 5-gallon size). Plant two to three potato eyes 2 to 3 inches from the bottom of the pot, and then water them in. After the plants start to grow, cover the stems with more soil (leaving the very top exposed) until the pot is full. In a couple of months, you can harvest a pot full of spuds. Start harvesting earlier for new potatoes, later for larger ones. (For more on growing potatoes in small spaces using towers, see Chapter 6.)
Radishes: Growing radishes is quick and easy even in the smallest container. Scatter some seeds in the top of a pot, keep the soil moist, and you'll have radishes in less than a month.
Squash: I have to be honest; bush zucchini plants are too productive even in pots. Use a 5-gallon pot (or even larger) to grow space-saving winter squash varieties like ‘Cornell Bush Delicata', ‘Papaya Pear', or ‘Table King'. Plant three seeds in each pot and thin to the healthiest plant.
Tomatoes: Everyone deserves fresh tomatoes, and anyone can grow them in pots. Try your favorite dwarf indeterminate variety, such as ‘Bush Big Boy' in a container that's at least 5 gallons (bigger is better), but be ready to stake or cage tall plants. Or you can grow dwarf varieties like ‘Patio', ‘Tiny Tim', and ‘Window Box Roma', which fit perfectly in pots, even smaller sizes.
Most herbs grow well in containers; see Chapter 12 for details.
Some bee-u-tee-ful vegetable combos
I'm a firm believer that anything growing in a pot, including vegetables, should look good enough to place on a patio or deck. So I like to combine different vegetables that look good together, and sometimes I even throw in some flowers. Here are some of my favorite container vegetable combinations:
Mixed leaf-lettuce varieties: All the different reds, greens, and purples form a soft, textured kaleidoscope of colors. You can sow premixed seeds, but I prefer to use transplants so that I can evenly space them for a more structured look.
Cool season masterpiece: In a half barrel, place one or two red Swiss chard plants in the middle, and then surround them with red and green leaf lettuce, a few parsley plants, and some white pansies.
A salad bowl: Plant some different lettuces or other greens with parsley, chives, green onions, and other herbs. (Are you starting to see how much I like to use lettuce as an ornamental?) If you really want to get fancy, add some edible flowers like pansies and violas. (For more on growing herbs, check out Chapter 12.)
Tomatoes and herbs: Plant one of the smaller tomato varieties, like ‘Patio', in the middle of a large pot. Surround it with basil or thyme, and mix in several dwarf yellow marigolds (which are edible flowers).
Cabbage and kale: A large pot works best with these vegetables. Just mix red and green cabbage with some crinkly kale. Keep the older leaves trimmed so that the arrangement looks nice and clean. If you really want a knock-out display, plant some red tulip bulbs about 4 inches deep in the soil.
Well, I've given you five good combinations. Using your imagination, you should be able to come up with plenty more possibilities. But do you want one more for the road? Try planting rhubarb in a pot; the big leaves and colorful stems are stunning.
Planting Your Veggies in Pots
Planting in containers is very much like planting in open ground (see Chapter 13). But with containers, you can plant seedlings or seeds a little closer together because you're concentrating water and nutrients in a small space, so the seedlings and seeds, not the general soil, get more of what they need to grow. You also don't have to form berms or basins in the soil with container gardening.
Here's how to plant vegetables in a container:
1. Fill your container with soil mix so that the soil reaches almost to the top of the container, and then wet the soil thoroughly.
Wetting the soil will probably take several passes with a hose. After the soil drains, it will have settled several inches.
2. After the water settles, add more soil until the soil level is within 2 to 3 inches of the rim.
Level the top of the soil with your hands.
3. Plant your seedlings or seeds.
If you're planting seedlings, make a small hole in the soil for each transplant. Place one seedling in each hole. The top of the root ball (the soil held together by the roots) should be level with or slightly below the surrounding soil. Use your finger to gently press down the soil around each seedling.
If you're sowing seeds, plant them at the appropriate depth according to the information in Chapter 13.
4. Water the container gently with a watering can or hose until the soil is thoroughly moist.
A watering can or a hose with a bubbler extension works best because it's less likely to wash soil out of the pot or dislodge seeds.
Care for your new plantings as described in Chapter 13, making sure to keep the soil moist until the seedlings are established or until the seeds germinate.
Caring for Container Veggies
Planting vegetables in containers is very much like planting them in the ground, but you must do a few things a bit differently when it comes to maintaining them. Here are some pointers for taking care of your container vegetables as compared to vegetables in your garden:
Water more frequently. Because potting soil dries out faster than regular garden soil, container vegetables need more frequent watering (unless you're using self-watering containers, which I describe earlier in this chapter). In really hot weather, you may have to water more than once a day, especially if the plants are large and roots fill the pots. If you let your vegetables go dry just once, you may spoil your harvest, causing conditions such as blossom-end rot, which can affect tomatoes. (You can read about how this condition affects tomatoes in Chapter 4.)
Here are a couple ways to check whether your container is dry:
• Stick your finger in the soil. If the top few inches are bone dry, you should water.
• Lift or tip the container on its side. If the soil is dry, the container will be very light.
Water more thoroughly. Wetting dry potting soil can be tricky. Sometimes, the root ball of the plant (or plants) shrinks a bit and pulls away from the side of the pot as the soil dries so that when you water, all the water rushes down the space on the side of the pot without wetting the soil. To overcome this problem, make sure you fill the top of the pot with water more than once so the root ball can absorb the water and expand. In fact, you should always water this way to make sure the root ball is thoroughly wet. It's also important, however, to avoid overwatering the soil; do the finger check before watering.
If you still have problems wetting the root ball, place your pot in a saucer and fill the saucer repeatedly with water. The water soaks up into the root ball and slowly wets all the soil.
If you have a lot of pots, you may want to hook a drip irrigation system to an automatic timer to water them; nurseries and garden centers sell special drip emitters designed for pots. You can find out more about drip irrigation and emitters in Chapter 15.
Fertilize more frequently. Because nutrients are leached from the soil when you frequently
water container vegetables, you need to fertilize your plants more often — at least every 2 weeks. Liquid or water-soluble fertilizers (you just add them to water) are easiest to use and get nutrients down to the roots of your plants. A complete organic fertilizer is best. (See Chapter 15 for more detailed fertilizer info.)
Watch for pests. Worried about insects and diseases harming your container plants? Don't be too concerned. In general, vegetables in containers have fewer pest problems because they're isolated from other plants. Insects aren't waiting on nearby weeds to jump on your plants, and sterilized potting soil (which I recommend for container gardening) doesn't have any disease spores.
Even though container vegetables tend to have fewer pest problems, you should quickly deal with any problems that arise so your whole crop isn't wiped out. Solve your pest problems by using the same techniques that you use in your garden. Check out Chapter 17 to read about controls for specific diseases and insects.
Because container vegetables are often located on patios or decks that are close to the house, special care should be used in spraying them for pests. I know I said container vegetables don't get as many pests as in the garden, but you may have to spray occasionally; so, if possible, move the containers away from the doors and windows when you spray.
Experimenting with Greenhouses, Hoop Houses, and Hydroponics
You can grow cucumbers, tomatoes, and other vegetables in the dead of winter in a greenhouse (an enclosed, heated, controlled-atmosphere room). In fact, farmers throughout the world do it all the time. You don't even have to have a glass structure for a greenhouse. You can use plastic hoop houses instead. They're easy to build, inexpensive, and a great way to extend the growing season. (See Chapter 21 for more on hoop houses.) Either way, greenhouse growing is more involved — it's container gardening and vegetable growing at their highest levels; everything has to be just right to get a good crop. But maybe I've helped turn you into a really good gardener, so everything will be just right. After all, that was the point of this book.
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