Peas and corn: a garden symbiosis

Peas are a delightfully, delicious, and easy vegetable to grow. Corn is a little trickier but just as delicious. Let's take a look at the benefits of growing them together.

When growing peas and corn together in a mutually beneficial arrangement, it is important to choose a corn variety that will grow tall enough to support your choice of pea. Timing is crucial to ensure the corn stalks are mature and strong when the pea vines need a trellis, and there are many ways to plan your planting layout that can be both practical and attractive.

Using corn to support vine crops is an old practise. Many aboriginal communities in North America planted the Three Sisters: beans, corn, and squash. The beans climbed the stalks of corn while the squash covered the ground. We are going to discuss growing corn and peas together in a similar manner.

Peas and corn are very different from each other but they can have a symbiotic relationship. Let's look at what each crop needs, and then how they can work together to benefit your garden.

READ NEXT: Grow Asparagus peas for an edible and ornamental garden.

Growing Peas

Peas are one of the easiest vegetables to grow, which is why they are ideally suited for a children's garden. Put a seed in some dirt and they will often grow. Of course, many seasoned gardeners know numerous ticks and tricks to grow this prolific vegetable, and most people have experienced a sad year when their peas didn't germinate or didn't bear flowers.

Image by Carmen Edenhofer

The Long And The Short Of It

Pea vines grow to a variety of lengths, from short bushy varieties less than a meter to some reaching 2.5m (8ft) and beyond. Some will give you peas to snack on in less than sixty days, while others will take over 70 days. Choose a variety that matches your growing season and garden desires, and also fits with your corn plan (more on this later).

Planting Peas

Peas are a cool-season crop, and can usually be planted directly into the garden as soon as the soil can be worked. The ideal soil temperature is from 10 to20°C (50-70°F). The seeds will sprout quickly (which is why they are ideal for children) in one to two weeks.

The seeds should be sown 2cm to 5cm deep (1-2 inches), and can be spaced 5cm to 8cm (2-4 inches)

Growing Corn

Corn can be a tricky plant to grow, especially if you want to have nice, fresh cobs to eat in the fall. Corn needs full sun and high heat, and many locations do not have enough hot days in their growing season for corn ears to fully mature. But don't let this discourage you. There are many cool-season varieties out there, and many local seed growers are bringing back heirloom varieties. These are the types of corn that our ancestors grew before the agriculture industry developed them into high-yielding, heat-loving mega-corns. The heirloom corn varieties are perfect for the homestead or the backyard garden.

Image by Bicanski

Heat Units

Most corn will typically take 80 to 100 days to reach maturity, though short-season varieties are available. However, just as important (perhaps more important) as the number of days is the "heat units" available in your area. An ear reaching maturity is controlled by heat units and this why it is often difficult to get your cobs to develop into a succulent summer dinner.

Generally speaking, temperatures above 10°C (50°F) will contribute to heat units. Each corn variety will need a certain amount of heat units to allow the heads to properly mature in time before the frost sets in.

Read Next: How to grow peas all year long.

Which Variety Of Corn?

There are many varieties of corn on the market as we already discussed, and there are other aspects to consider when growing them with your peas. How many days it takes to reach maturity and the corresponding heat units is important, but so is height. The mature height of your corn should match how tall your pea vines will grow.

When you plan on harvesting your corn is another factor to consider. Planting a mid-season variety, for example, has the advantage that the corn can be harvested early so it doesn't block the sun from the peas. On the flip side, it might be beneficial to harvest your corn after your peas have finished producing so the pea pods do not take valuable nutrients away from the maturing cobs. Find what works best for your arrangement and location.

Planting Corn

Corn should be planted when the soil is at least 18°C (65°F). Otherwise, the seeds will rot or simply won't germinate. The soil will need to be warmer for super-sweet varieties. Corn plants are a heavy feeder, and they greatly benefit from lots of compost and manure to provide food for the ears.

Plant the seeds about 2cm to 5cm (1-2 inch) deep, and allow 7 to 10 days for them to germinate.

Growing Peas And Corn Together

Peas and corn are ideal planting companions. They interrupt the life cycles of diseases and insects that bother the other. The peas provide large amounts of nitrogen for the hungry corn. The corn creates a cool environment for the peas in the hot summer while the thick stalks make a natural and sturdy trellis.

As we mentioned before, one of the most important parts is choosing two varieties that complement each other. Make sure that your pea height will not exceed the height of your corn.

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Plot Layout

When you are planning the layout of your peas and corn, keep in mind that corn is wind-pollinated. Planting in a block or circle will greatly benefit the corn, and it can look very aesthetic as well. Or, get creative and plan a decorative yet practical pattern. As with any vertical garden, it is important to ensure that both plants get the sunlight they need.

There are many ways to plant these two vegetables together. You can interplant them in the same row. Corn seedlings are generally thinned so they are spaced every 25cm (10inches) or so, though large-eared varieties need 60cm (24inces) between them. Most pea seeds can be planted just a few centimetres apart, so you can have quite a few peas between each corn stalk. However, it is important to thin out the seedlings more than usual to avoid choking anything out. Though corn stalks are tough, you also do not want to put too much weight on each corn plant and risk them breaking.

Another option would be to plant a row of peas beside rows of corn, and the peas can be trained up their tall neighbours. A more ornamental pattern would be to plant a single corn plant surrounded by a circle of peas and create a natural teepee.

The possibilities are limitless. You might prefer a purely practical garden with straight rows to minimize distractions and maximize production. Or you might be creating an edible work of art or a combination of both. Create a layout that fits your garden.

Image by Carmen Edenhofer

Timing

Traditionally, corn was grown with beans, which simplified planting time because corn can often be started first. The beans are typically planted when the corn is 15cm to 20cm tall. This gives the corn a head start before the beans needed trellising. This is a little trickier with peas since they can be planted before corn in many areas.

One solution is to start the corn early indoors. This will ensure the corn is large enough when it is transplanted to the garden to begin supporting the peas.

If you want to direct sow both crops, you might want to delay the peas a few weeks to give the corn time to get established. You could also use a few sticks to hold the peas erect while they are young. The corn will be strong enough to take over to support the peas once the vines outgrow the sticks.

Growing Together In Cold Climates

If you live in a location where growing corn to maturity is a hopeless endeavour, it is still beneficial to grow these two crops together. While your corn may not produce ears, it is still a beautiful plant and can create a scenic background for your peas. It is also a natural material for a trellis and can be added to the compost at the end of the year.

And you never know, one year you might get lucky, and be rewarded with a both plants producing an abundant harvest.