Tag Archive | ‘Nabechan’ bunching onions

Vegetables in Containers: How To Grow Them

2018

No Garden Space? No Problem!

Growing Vegetables in Containers

Peppers and onions.

Before I started this blog, I managed the Edibles Department for a few years at an independent garden center in Charlotte, North Carolina. As some of our customers downsized to apartment living or to a condo with a balcony, they didn’t want to give up growing their own herbs and vegetables. So, they were glad to hear that they could grow vegetables in containers…as long as the balcony was on the right side of the building. And the right side for vegetables is the sunny side of the building.

Lack of direct sunlight and adequate growing space are limiting factors. Look around, though, and you might come up with some ideas. For example, some of our customers were given permission from their condo associations to garden in common areas. Running for open association board positions yourselves is one way to garner support. I encourage you to attend board meetings, bringing your neighbors, a plan, and a promise to maintain the site.

Neighborhood community gardens are another possibility, although there often is a waiting list. With so much emphasis on eating healthy foods, little pocket parks and community gardens are popping up all over the country.

For Your Convenience

A young tomato damaged by a squirrel.

Another reason to grow vegetables in containers is simply to have them close at hand when they’re needed. A few steps out the kitchen door to a handful of cherry tomatoes and a ripe ‘Flavorburst’ sweet pepper for today’s salad has its charms.

Keeping the pots elevated on the deck prevents some animals, such as deer and rabbits, from making off with the fruits of your labor. Won’t stop the raccoons, though. (***Update***: Or the squirrels; one thought this little green tomato had something to offer. Discard any fruits that have been chewed on by animals. If needed, I’ll wrap the potted tomato plants, growing on the deck, in bird netting. June, 2019.)

Sun? Not So Much

The choices for edibles in a shady spot are limited. The ones that might succeed in bright shade are arugula, cilantro, parsley, lemon balm (interesting research with Alzheimer’s), French sorrel, and seasonal leafy greens. With just a bit more sun, basil, rosemary, oregano, and maybe a cucumber plant could grow for you.

Reflected light counts, to a degree, including light bouncing off light-colored walls. And a white surface under the pots reflects more light onto the vegetables in containers.

Remember to monitor the sun’s path throughout the seasons. Once trees drop their leaves in the fall, your balcony or patio might receive more direct sunlight than it did in the summer. This opens up all kinds of possibilities for potted cool-season greens and vegetables. Pay close attention to expected temperature changes for the duration of your crops.

Fruiting plants, such as tomatoes, peppers, eggplants, and squash need at least 6, and preferably 7 or 8 hours of direct sun. These vegetables also need warm summery weather.

Approaching Summer Solstice

Our vegetable garden is now receiving the maximum amount of light, with the sun directly overhead. In the springtime of the last two years, heavy rains caused the tree canopy up on the berm, to the south, to swell with heavy, overhanging branches. Trees now cast considerable shade early and late in the day for most of the growing season. So, I planted fewer tomato plants and more greens.

Two large ‘Big Beef’ tomatoes are beginning to ripen, and a whole lot of ‘Sun Gold’ and ‘Mexico Midget’ cherry tomatoes. So, even with less than ideal conditions, there will be something to harvest.

At Julia’s Request

Several family members from New Jersey and California recently visited us in North Carolina. I promised Julia this article about growing summer vegetables in containers.

Vegetables In Containers: Which Ones?

: Potted green onions.

: Potted tomato.

Sweet and hot peppers, tomatoes, and eggplants can be grown in containers, as well as zucchini, yellow summer and Patty Pan squashes, cucumbers, and green beans. Also, it’s easy to grow most herbs in pots. Green onions, carrots, potatoes, and peas can grow in pots!

It’s just a matter of the details. One of those details is to look for dwarf or bush varieties of the crops you want to grow. There’s even a variety of corn (‘On Deck’) that grows in large pots.

One of the popular combinations I used to sell included a sweet or a hot pepper planted with two herbs. Theme combinations (‘Jalapeno’ pepper-cilantro-Greek oregano; ‘Carmen’ frying pepper-Italian oregano-dwarf parsley ‘Titan’) grew in 14″ pots. Customers found them irresistible if they were bearing fruit.

Growing more varieties of leafy greens in containers has become a priority as our garden becomes more shaded. In addition, greens can grow all year in regions with moderate winters.

Starting With Tomatoes

Much of the information in “Starting With Tomatoes” also applies to other vegetables in containers.

Potted ‘Blueberry’ cherry tomato.

Beginning with America’s favorite, tomatoes grow well in pots. Will it be a beefsteak or a cherry? An heirloom or a modern hybrid? A slicer or a sauce-type? Determinate? Indeterminate (it keeps growing until frost, bearing fruit all summer)? Black, red, yellow, or orange? Striped or solid? There are many thousands of varieties of tomatoes to choose from!

‘Terenzo’ tomato.

A dwarf tomato called ‘Terenzo’ (photo, right) can grow in a 10″ hanging basket, but a ‘Cherokee Purple’ heirloom or a ‘Big Beef’ needs something considerably larger. For the large varieties, I use pots at least 20″ in diameter.

The long-vining indeterminate cherry types (‘Sun Gold’, ‘Black Cherry’, ‘Mexico Midget’) can grow in a pot as small as 14″ in diameter, but they’d be happier in bigger pots. You’ll need to pay closer attention to water and fertility when using smaller pots.

Vegetables In Containers: Types Of Pots

Each kind of pot has both advantages and disadvantages.

Summer vegetables generally fare better in larger pots rather than smaller pots. Although the pot looks enormous compared to the transplant’s diminutive size, don’t be tempted to plant more than one tomato per pot. You’ll be amazed how quickly that one tomato plant fills a 20″ pot. A new transplant in a large pot runs a greater risk of root rot during rainy weather. But, placing it under an overhang will prevent this loss. It’ll be different once more roots and foliage have grown.

An indeterminate tomato, such as ‘Cherokee Purple’, ‘Sun Gold’, or ‘Black Krim’, can share a 20″ diameter pot (photo, below) with a couple of herbs, such as parsley and oregano. Plant the tomato toward the back of the pot, on the north side (northern hemisphere), and plant the herbs near the southern rim.

Terra Cotta

Terra cotta looks good and has some weight. But clay is porous, so water vapor passes through the pot to the air outside, quickly drying the soil. If you want to use your large clay pots, you could line them with food-grade plastic and punch some holes in the bottom for drainage. This will slow down the evaporation process.

Certainly, use clay pots if you prefer, but prepare to water more often.

Ceramic Pots

Ceramics are beautiful and heavy, and can be expensive. Soil temperature rises uncomfortably on the sunny side unless the pot is shaded. Try using light colored pots in the summer, which will reflect most of the heat.

If you’re unsure of the safety of the glaze, line the inside of the pot with food-grade plastic bags, poking several holes in the bottom for drainage. But, I would choose a different pot if a sticker on the bottom warns “Not for direct contact with food”.

You could also plant the tomato in a large nursery pot, and then insert it into the decorative glazed container. Make sure both pots have drainage holes. This “double-potting” allows air circulation around the interior pot and eliminates concerns about questionable glazes.

Tomato ‘Rutgers’, sweet basil, and Italian parsley in a 20″ wide pot, April, 2019.

Plastic and Vinyl

These pots are inexpensive, readily available, and easily moved. They’re also the most likely to blow over in windy weather. But this is the first choice for most gardeners. Most of these pots last a few to several years in the sun, but, eventually, sunlight will degrade the material.

Wood Containers

Untreated cedar or redwood and half whiskey barrels are suitable for growing vegetables in containers. Check to make sure the pots drain freely.

Reservoirs and Other Considerations

Earth boxes and plastic pots often have built-in reservoirs or detachable saucers. And you can purchase caster kits and trellises for increased functionality. Some gardeners have the option to move their plants from the morning sun on one side of the deck to the afternoon sun on the other side; wheels make this so much easier.

Caution: some of the reservoirs are too deep before the water begins to exit the overflow hole, and can cause young plants to rot if the soil stays sodden all the time. You could drill a hole in the side, below the overflow hole, reducing the capacity of the reservoir. Or simply tilt the pot to allow excess water to drain. Older plants, full of foliage, will absorb water in the bottom of the planter, as long as it isn’t raining for several days straight.

Mosquitoes and Tree Roots

Add a piece of Mosquito Dunks to prevent mosquitoes from maturing in the secluded reservoir. They need only a few days in warm weather to complete their life cycle. Or tip the container to drain all excess water.

A pot sitting directly on soil anywhere near trees or shrubs will invite their roots to invade. Believe me, they will try to grow in that beautiful composted soil. Elevate the pot off the ground. This also facilitates drainage from the pot.

A few pieces of broken flagstone or “pot feet” raise the pots above the surface of the deck, helping to preserve the deck’s finish.

Saucers

Use saucers under the pots, but don’t let water remain in them for more than an hour. Plant roots need oxygen as much as they need water. Water in the saucer prevents air from entering the bottom of the pot.

Saucers aren’t absolutely necessary, but help if the soil has gone too dry. Just keep filling them until no more water is absorbed by the soil. In tall pots, though, the force of gravity will prevail over capillary action, preventing water from reaching the top of the root ball. So, you’ll also need to water the top portion of soil.

During long periods of rainy weather, I remove the saucers, or turn them upside down and keep them under the containers. This is impractical, however, if the pot weighs 50 pounds. Consider removing the saucer and using a few pieces of broken flagstone or brick to elevate the pots, if necessary.

Potting Soil

Reused polyester fiberfill covers the drainage hole.

Before filling the pot, place a small handful of polyester fiberfill (from a hobby store) over the drainage hole. This prevents soil from eroding through the hole, and prevents earthworms and other critters from entering. If you pull some of it through the hole to a point at the bottom, excess water will continue to drain. This is helpful for potted plants that rot easily during long stretches of rainy weather (succulents, lavender, thyme, sage). This synthetic material doesn’t rot, so it’s reusable.

Use a good quality potting soil that drains well, but has peat moss to hold moisture. In addition to the peat moss, the mixture will have perlite (white particles that help drainage), pine bark chips (drainage), lime (to adjust the pH), compost or a starter charge of fertilizer, and often a wetting agent (to help the soil absorb water).

Amending the Potting Soil

Feel free to experiment with mixtures of different materials. Soils with a lot of bark (pine fines) in the mix tend to dry out faster. You can mix in smaller-particle loamy topsoil, spongy peat moss, aged manure, or compost to help slow water loss. Water-absorbing crystals might help, too. But moisten them before you add them to the soil. If you don’t, you’ll understand why I italicized the word “before”.

Adding a layer of undyed mulch on top of the soil helps conserve water and keep the soil a bit cooler.

While some gardeners add rocks to the bottom of the pot, I never do. It was thought the rocks increased drainage, but the opposite is true; they create a perched water table in the layer of soil right above the rocks. Water percolating through the soil profile is held in this layer by capillarity, and often rots roots trying to grow there, limiting the useful volume of soil.

Headings

Page 1: Growing Vegetables In Containers, Sun? Not So Much, Vegetables In Containers: Which Ones?, and Starting With Tomatoes (Vegetables In Containers: Types Of Pots, Reservoirs and Other Considerations, Mosquitoes and Tree Roots, Saucers, Potting Soil (Amending the Potting Soil)…

Page 2: Transplanting the Tomato, Water, Going Away?, Staking, Fertilizing Vegetables In Containers, Blossom End Rot, On PH, Pollination), Peppers and Eggplants, Cucumbers, Squash (Squash Vine Borers), Green Onions (Bunching Onions from Seed), Leafy Greens, and Picking Vegetables In Containers

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Did She Say Sustainable Bunching Onions?

May15

updated 3/8/2024

The Onion Patch

In a patch of soil under the cold frame in the old Maryland garden, I grew several dozen Japanese bunching onions. Although the frame was cold in the winter, it didn’t freeze, and those little plants provided us with all the green onions we needed for 5 or 6 years without replanting!

So, how do you get sustainable bunching onions? After describing two species of onions and sowing seeds, I’ll explain the “sustainable” part.

Bunching onions purchased from the grocery store.

Two Species of Onions

Allium Cepa, the Bulbing Onion

Allium cepa is the commonly grown bulbing onion. Onion sets, small immature bulbs, can be purchased from garden centers in late winter and sometimes in autumn. Plant onion sets a few inches underground, and pull them as green onions before they form bulbs. Planting sets every couple of weeks will provide a continuous harvest.

Left longer in the garden and spaced properly, though, the bulbs will grow larger. Your garden’s latitude, which affects day length in the growing season, will determine which onion varieties will successfully form bulbs. Short-day onions are grown in the southern United States, and long-day or intermediate varieties are grown farther north.

Check with your local agricultural extension office for names of varieties that will mature as bulbs in your region. Bulbing onions also can be grown from seed or purchased in bunches of young seedlings, but most varieties require more than 110 days to mature.

Allium Fistulosum, the Bunching Onion

The variety I grew in the cold frame was called ‘Nabechan’. This variety is a member of the species, Allium fistulosum. Japanese bunching onions, or scallions, don’t grow bulbs. Several varieties are available, and all remain straight-sided, with minor swelling at the base. Bunching onions are available as seeds for home gardeners.

Bunching onions are the ones usually sold in small bunches at the grocery store (photo, above). I use them in salads, omelets, stir-fries, and soups. Once or twice a week, I add a green onion to the spinach, mushrooms, a colorful lunchbox pepper, and kale in the veggie omelet. It’s really good with cheese and microgreens or slices of avocado in the fold…maybe some bacon on the side, and rye toast.

Although both species of onions can be harvested as green onions, the ones I sold at farmers’ markets were ‘Nabechan’ bunching onions. They were ready for the market when the 15 or 20 seedlings in 6″ or 6½” pots approached a harvestable size. Here’s how to grow them, if you’d like to give it a try.

Starting Seeds For Bunching Onions

Sow the seeds 1/4″ deep and about 1/4″ apart in 6″ pots filled with seedling mix. Water gently, so the seeds aren’t dislodged. They germinate well at temperatures around 70° to 80° F.

When the seeds germinate, give them full direct sunlight (6 hours at least), and lower the temperature. They thrive with cool to moderate temperatures, but avoid subjecting them to frost at this early stage. Inadequate light creates weak seedlings and feeble roots.

Keep the soil moist. Onions have shallow roots, and fail when grown too dry. Fertilize every 2 weeks with fish emulsion, Sea-Plus, or any complete fertilizer.

Transplanting Seedlings Of Bunching Onions

Once they’ve grown a few inches tall and are easier to handle, the seedlings will need to be spaced farther apart.

First, fill the new pot or pots with dampened potting soil to within 4-5″ of the rim. Yes, that seems too low, but more potting soil will be added as the seedlings grow. Firm it in lightly.

Where To Place the Crown

Now, gently ease the young plants and the soil mass out of the pot. Don’t let exposed roots dry out during this process. Cover them with a damp towel as you work.

You’ll see the 3 main parts of the onion: the green leaves, the white roots, and the region between the leaves and the roots, called the crown.

Hold up the seedling’s leaves and transplant it into the new pot. Space seedlings 3/4-1″ apart. It might be easier using a pencil to poke a hole into the soil for the roots. Plant with the crown at the soil surface, and lightly firm the soil around its roots. Add a small amount of potting soil over the bases of the stems to stabilize them. Plant them in wider nursery pots, if you choose, where they can remain until harvested. But they won’t require a deep pot.

Water the seedlings and place the pot in direct sun. But avoid harsh hot sun for a couple of days while the roots recover.

Growing Long White Stems

The trick to getting those long white stems is simply to plant the seedlings lower in the soil. Excluding light prevents chlorophyll from developing, blanching the stem. Leeks, another member of the Amaryllidaceae family, get their long white stems in the same way.

Every 10-14 days, add soil between the seedlings, an inch or so at a time, while holding the leaves upright. Although this sounds contrary to normal horticultural practices, the onions will recover. Chlorophyll in the covered stems will be reabsorbed by the plants.

Older leaves will turn brown and can be removed. But strong new foliage will emerge while the underground stem continues to thicken. It’s important to give seedlings full sun for optimal photosynthesis.

The pot is finished when the soil surface is about 1″ below the rim of the pot. The bunching onions will have 4″ or 5″ of white stem below the green leaves (longer than in the photo of store-bought onions, above).

Introduce the seedlings to stronger sun and cooler temperatures outside in the daytime. Protect them from frost while they’re hardening off. With good growing conditions (direct sun, moderate to cool temperatures, moist soil, and fertilizer every 2 weeks), the onions can remain in pots until they’re harvested.

Here’s Another Method of Seeding Bunching Onions

‘Evergreen’ bunching onions.

In the photo above, I started seeds about 1½” above the bottom of a 6½” pot, and spaced them farther apart. Adding soil every couple of weeks blanched the stems. Spacing them farther apart from the beginning obviates the need for transplanting.

I tilted the pot on the plant stand outside so the seedlings could catch the rays of the low sun during the shortest days of the year. On cold nights, the pot came indoors. These are seedlings of a variety called ‘Evergreen’.

Planting Bunching Onions Outdoors in the Garden

If you want to grow bunching onions in the ground, plant the pot of seedlings as a unit, covering the stems with 1″ to 2″ of soil. With good soil preparation and careful monitoring, young seedlings can be transplanted into the garden at this stage, weather permitting.

Seeding directly into prepared garden soil is another option if you can monitor progress and keep pests away. Remove weeds when they’re small; onions’ roots can be damaged even with shallow cultivation. By the way, deer and rabbits don’t eat onions.

As the seedlings grow, occasionally hill up soil around the base of the plants to lengthen the white stems. Within about 2 months of seeding, the bunching onions are ready to pull as needed in the kitchen. Younger plants are especially delicate and tender as a garnish. If they’re spaced an inch apart, the seedlings won’t need to be thinned.

Non-bulbing onions are easier to pull from the soil than other types of green onions that have begun to form bulbs. That’s why I prefer growing Japanese bunching onions for green onions. If needed, use a narrow trowel or a butter knife to help pry them from the soil if you want to harvest the whole plant or if bulbs have started forming when using onion sets.

Negi Onions

Bunching onions traditionally are sown in cell packs with several seeds per cell. Later, they’re planted out without separating the seedlings, allowing them to grow and be harvested as a “bunch”. But, in order to grow “sustainable” bunching onions, they need to be grown separately from each other.

In the popular “Negi” method of growing bunching onions, seedlings are spaced farther apart from the beginning and hilled deeply over time. These scallions are older and larger than the ones I grow, resembling leeks.

Here’s the Sustainable Part

This is where bunching onions become sustainable bunching onions.

Instead of pulling out the entire plant when harvesting, insert a knife into the soil a few inches, making a cut through the stem 1/2″ to 2/3″ above the root system. By leaving the bottom of the stem and the roots intact, the plant will regenerate and give you another green onion after 2 or 3 weeks of favorable weather!

Experience will sharpen your aim, but whether the stem was cut too high or too low, it doesn’t matter. It’s all edible. If you removed the whole stem accidentally, just cut off the bottom 1/2″, with roots, and replant 2″ below ground. It’ll take longer to grow, but it probably will survive.

With some protection in colder climates, it’s possible to harvest mature bunching onions all winter long. That’s why I grew them in a cold frame. Just be sure to plant enough of them. Depending on the temperature, they might remain semi-dormant and not regrow until the soil warms up. And what a surprise to see them vigorously re-emerge in the spring to provide another year of harvests!

“Can I Plant Bunching Onions From the Store?”

Cut stems from the grocery store, later planted into a pot.

Sure can! Buy a bunch of green onions (as in the photo at the top), looking for those with clean white roots. Choose the stems you intend to use in cooking, and cut 1/2″ above the crown. Don’t let them dry out, and plant 2″ deep into a pot of lightly moist soil as soon as possible. Adding more soil later will lengthen the white part of the stem. Cut stems initially planted too deeply might exhaust themselves before reaching the light.

In the photo above, I cut these bunching onions over a period of a few days, and placed them in a clear plastic bag with 2 drops of water. Until a pot of soil had been prepared, the bag sat on the counter, in bright indirect light. You can see the older ones already sprouting. Growing onions in water, even short term, can turn them mushy and really smelly. That’s why planting them directly in soil is preferred.

Keep the pot moist and sunny, and you’ll see a green onion growing probably within 7 to 10 days during the growing season. In the middle of cold winter weather, though, keep the pot in a cool but sunny window indoors or in a cold frame. Soil that freezes could kill the root at this stage. Pick the entire plant or cut the stem when it has grown to the desired size.

Bottoms Up!

If you’re growing green onions from onion sets, this is one of the easiest crops to grow. Seedlings take a little more patience. Because they retain good flavor and substance for a long time, you can harvest what you need and let the rest of the bunching onions continue to grow. Sometimes, all I need is a single green leaf for a small omelet or a garnish.

Here’s to sustainability! Oh, and the reason why those ‘Nabechan’ bunching onions in Maryland failed after several years: contractors replacing the siding on the house trampled them to mush.

These were planted as onion sets in late winter, before starting seeds of bunching onions. They’ll be harvested as green onions or when they have small bulbs.