Don’t be embarrassed – it happens to the best of us. You invested money and time into your precious pea seedlings, only to find after a few months that they aren’t doing well at all. Before you write off this season as a loss, let’s uncover why your peas aren’t producing, and what adjustments you can make to save this season’s crop.
Peas are not difficult plants to grow, but they are particular about weather and soil conditions. If your peas have stunted growth or aren’t flowering, the problem could be as simple as hot temperatures or as complex as a nutrient deficiency.
Either way, there are several steps you can take to remedy the problem and still harvest peas this season. Read on to learn about which factors inhibit pea production and how to avoid the same mistakes next season!
Troubleshooting 4 common scenarios
There are four common scenarios that gardeners face when it comes to pea growth.
- Peas have stunted growth
- Peas have wilted or discolored foliage
- Peas aren’t producing flowers
- Peas have flowers but no seedpods
Each of these scenarios is usually caused by some combination of the following factors.
8 factors that affect pea health and production
1. Hot and dry weather conditions
Peas are a cool-season crop, and if the plant wilts and foliage turns shades of yellow and brown, that’s a sure sign of heat stress. Peas can be grown as an annual in all hardiness zones, but they do better as spring crops in harsh climates and fall and spring crops in temperate climates. Peas prefer full sun for the most productive plants, but partial shade and protection from the afternoon sun will benefit peas sown in hotter regions.
Some pea varieties are better suited to hot climates – sugar snap peas are more heat and drought tolerant than their cousins, snow peas and English peas. Snow peas and garden peas can also be grown in warm regions, but do your research and opt for early cultivars that mature quickly and are harvested before hot summer days begin to set in.
2. Soil pH and/or composition issues
If your pea plants seem to be stunted, the soil pH and composition may need to be adjusted. Peas prefer a pH of 6.0 to 7.5 – slightly acidic to neutral. Do a soil test so that you know what pH your soil is at, and adjust as necessary. If your pH is too low, add lime, keeping in mind that this will also add calcium to your soil. If the soil pH is too high, add sulfur.
Peas need well-draining soil to thrive. If water puddles around your pea plants, add compost, pine chips, or coarse sand to encourage drainage.
3. Soil has a nutrient surplus or deficiency
The number one reason that pea plants don’t flower is due to a nutrient surplus or deficiency – too much nitrogen or too little phosphorus. Peas actually don’t require much fertilizer, if at all. Peas are a legume, meaning that they work with a specific bacteria, Rhizobia, to capture nitrogen in the soil. The University of West Virginia Extension Science explains the symbiotic relationship this way:
When [Rhizobia] bacteria are living in the soil near the planted seed or are attached to the seed coat at planting, they enter the plant’s roots and multiply. The bacteria fix or capture atmospheric nitrogen gas, convert it to ammonia and make it available to the plant.
In a way, pea plants fertilize themselves – but they are helpless without Rhizobia bacteria. If your pea plants are having trouble metabolizing nitrogen, you may want to purchase an inoculant powder. If pea plants are exposed to too much nitrogen, they put more energy into growing foliage and stems, rather than roots and flowers.
If you aren’t sure what the nutritive makeup is of your garden soil, send it off to your local university office to get tested. If your soil is nitrogen deficient, you can apply a fertilizer containing a small percentage of nitrogen. Phosphorus is another useful nutrient to help plants develop strong root systems. Peas need phosphorus to flower and make fruit, so use a 5-10-10 fertilizer (5% nitrogen, 10% phosphorus, and 10% potassium). Alternatively, apply bone meal or rock phosphate if you are concerned about adding too much nitrogen to your soil.
4. Drought and water stress
Dehydrated pea plants will look wilted and have off-color foliage. Ironically, overwatered pea plants will show the same symptoms, so look to the soil to determine the diagnosis of your sick pea plants. If you suspect root rot, dig under the soil and check the roots. Slimy, brown roots confirm the presence of this fungal disease.
There’s not much that can be done for established root rot, but if caught early enough you can correct the issue by adjusting your watering habits. When possible, water in the morning to avoid a host of issues and potential diseases that come from watering plants too late in the day. A good rule of thumb is to water peas one inch a week once plants start flowering. Use a rain gauge to measure and record your plants’ watering needs.
If you anticipate having hot, dry weather, mulch your pea rows with composted wood chips or straw to hold moisture at the base of the plant. Mulching doubles as weed suppression and as an easy way to keep plants cooler in the early summer heat. In the event of a heatwave, use a bamboo screen to cast shade on your pea plants.
When planning next years’ garden, you may want to plant peas somewhere where they will get afternoon shade. Peas do grow faster in full sun, but partial shade may be the trick to lengthening their growing season in warmer climates.
5. Stress from disease or pests
Peas suffering from pest pressure or disease will have stunted growth and visible foliar damage. Even inoculated pea seeds or disease-resistant varieties will still be at some risk for pests and disease. While there is no way to completely eliminate the danger for both in your garden, you can incorporate several habits that may keep your plants healthier for longer.
Companion plant your peas with other vegetables and herbs that deter pests, including turnips, which deter aphids, and basil, which repels thrips. Release beneficial insects, like ladybugs and lacewings, into your garden. Pea seedlings are most at risk when newly transplanted, and you may opt to cover plants with row cover if the bugs are really bad.
Some diseases, like powdery mildew, set in towards the end of an annuals’ growing cycle. Powdery mildew won’t kill your pea crop, but it will slow down production. To treat powdery mildew, make a spray of 1 tablespoon insecticidal soap or Castille soap, and 1 tablespoon baking soda with 1 gallon of water. Apply the spray directly to pea foliage in the morning or evening. Be sure to wear gloves and mask when spraying, and wash peas well before consuming.
6. Weed pressure
Peas that are being overtaken by other plants may have stunted growth. Weeds compete with peas for water, sunlight, and nutrients in the soil. Weeds don’t have to be the only thing suffocating your peas, either. As ridiculous as it sounds, make sure that there’s not another garden crop overtaking your pea row. Peas need partial sun, and if they’re being shaded out by another crop in your garden, they will be slow-growing and will not set many flowers or seedpods.
7. Lack of pollination
Peas with flowers, but no seedpods, might not be getting pollinated. If your peas are growing indoors or under plastic, pollinators may not be able to reach them, and no flowers equal no seedpods. Pea plants pollinate two ways – through self-pollination or through cross-pollination. Peas in an isolated area may need to be stimulated to self pollinate by regularly flicking the flowers or by incorporating a fan into the space to move pollen around.
Alternatively, you can buy pollinators like bumblebees and blue bottle flies to introduce to that space. If you check on your outside-planted peas periodically and don’t notice any native pollinators, you might want to consider growing pollinator-friendly plants nearby. Check your local nursery for plant starts.
8. You’re not harvesting enough
The more seedpods you pick, the more your pea plants will produce! When you allow too many seedpods to ripen past the perfect edible stage into the seed-setting stage, pea plants will naturally slow down. When you harvest, do a thorough comb-through of the bottom leaves and foliage closest to the trellis, to ensure that you aren’t leaving any seedpods on the vine.
Conclusion
Peas, whether they be English, snow, or sugar snap are some of the most rewarding vegetables you can grow in your garden. Peas are a cool-season annual and do require a little more maintenance than other crops, but the effort is worth it. Do your research, invest in good soil, water regularly, monitor pests and weeds, and your pea plants can’t help but thrive!
Sources:
Basden, Tom “Legumes & Nitrogen Fixation,” West Virginia Extension Service, 2021,https://extension.wvu.edu/lawn-gardening-pests/news/2021/11/01/legumes-nitrogen-fixation.
