Companion planting can be defined as the close planting of different species based on their ability to enhance one another's growth or offer some form of pest protection or other advantages. Sometimes this is a matter of choosing plants with different growth habits that don't compete with one another or those that have different nutrient needs that make efficient use of soil. Strategic companion planting is especially important in small gardens or wherever careful space planning is needed.
For peas, the best companion plants are the ones that share their care requirements, as well as help them grow better and/or use your gardening space more efficiently. Harvest time does not need to be the same. Plants in the allium family (onions, leeks,etc.) are not good partners for peas because they have a tendency to stunt the growth of peas.
Note that peas and other legumes, like beans, are good companion plants for many other vegetables since they increase the availability of nitrogen the soil. A great many vegetables are enhanced if they have peas and other legumes as close neighbors.
Best Companion Plants for Peas
Plants to Avoid Planting Near Peas
Peas are annual vegetable plants and so have to be planted anew each year. They are cool-weather plants, so think spring for planting time.
Conventional wisdom says to plant pea seeds outdoors by St. Patrick's Day (though this really works only in Zone 5 and higher). A better rule is to plant them outdoors about a month before the frost-free date in your area. You can check this on the website for the National Weather Service. The seed packet gives information on how long it takes the seeds to germinate, depending on soil temperature.
Peas aren't terribly particular about the soil they are in, but they prefer a fertile, well-draining medium. They have a more difficult time thriving in heavy clay soil. Since pea plants often don't survive transplanting, it is best to start them as seeds directly in the garden bed if that's possible. Plant in full sun for best pea production. Peas need little care once they are established. A deep watering weekly should be enough, but don't let the plants dry out--that diminishes pod production.
The key to knowing when the peas are ready for harvesting is in the pod. If it's bright green and round, with a bit of a shine, it's ripe. A dull green color means you've missed the pod's prime. Pea plants are relatively fragile, so be careful when you snap off the pods. Harvesting frequently encourages production.
As with most vegetables, peas from the garden are best when they are freshly picked. If you can't use them right away, they will keep in the refrigerator for about five days. If you want to store them longer, freezing is the best option. Peas can also be dried for long-term storage. They lose some flavor but still can make a tasty addition to winter soups and stews.