Yellow leaves on peas can be caused by a lack of sunlight, pests, poor soils and overwatering. Giving too much water to peas or heavy rainfall can wash nitrogen out of the soil causing the leaves to lack chlorophyll and turn yellow. Pests like aphids and scale can suck the sap from the pea leaves causing them to curl and turn yellow within a few days.
Check the leaves carefully for pests and treat the sap suckers with neem oil. Yellow leaves on peas can be easily fixed and this article will explore what to do to save your plants.
Top causes of leaves turning yellow on peas
Here are the top reasons why pea leaves turn yellow. Check out each one and see if this might be the cause of the problem for your peas.
1. Old lower leaves
Leaves that have turned yellow near the base of the plant are the older leaves. There will be the first 2 leaves the peas start with that will turn yellow quickly. This is a completely normal process, and the peas will produce larger green leaves at the top of the plant.
These yellow leaves will not cause any harm to the plant and can be left on. The plant will reabsorb the nutrients from these lower leaves and they will eventually shrivel.
2. Lack of nitrogen
Pea plants that lack nitrogen can develop yellow leaves. While peas are legumes so have the ability to fix nitrogen from the atmosphere in very poor soils they can still suffer and turn yellow.
For peas planted out in a garden bed, sprinkle a handful of pelleted chicken manure around the plant root zone to top up nitrogen levels. You will see the new leaves green up in this time and vine will grow long and green from the ends.
Before planting out new pea plants in very poor, sandy soil, mix through compost, aged cow manure and pelleted chicken manure.
3. Overwatering
Overwatering can cause pea leaves to turn yellow. Overwatering will wash nitrogen out of the soil and away from the roots. It can also compact the soil, causing the roots to rot and they won’t be able to get the nutrients they need.
Before watering peas check the soil first to see if it is dry 1-2 inches down. Water only when the top soil has started to dry out to avoid overwatering. Rain water is great for peas as it will contain small amounts of atmospheric nitrogen to help them to develop green leaves.
Mulch the plant with bark mulch or straw which will help to regulate the amount of water that runs through the soil. Bark mulch will absorb extra water and slowly release it over time. Slow down your watering schedule and allow time in-between watering for the soil to dry out slightly.
4. Pest attack
Pests can cause pea leaves to turn yellow. Sap sucking insects such as scale or aphids can sit on the leaf veins, sucking out the nutrients and water and causing damage to the leaf. The leaf will eventually turn yellow and then brown.
Look out for tiny green aphids or brown scale that hide near the leaf stems.
Scale
Scale are small beetle shaped insects which will suck the sap from your pea leaves. Scale can be treated with Eco or Neem oil effectively. Spray the bugs off with a strong jet of water if there are only a few but check your plant each day because they can quickly breed and take over.
Aphids
Small green aphids can attack peas sucking their sap and causing leaves to turn yellow. These insects will attack new growth and can appear quickly in the mild fall weather. Ladybugs will move in to eat the aphids if there are only a few. If the population gets large, spray them with Neem oil. Aphids can cause damage to young peas so deal with them quickly.
5. Underwatering
Underwatering can cause your pea leaves to turn yellow. Peas growing in sandy soil can dry out quickly. Unseasonal hot weather can dry peas grown in full sun quickly causing the leaves to turn yellow and then brown. These are great winter plants but if you get a sudden hot spell, make sure you add extra water to keep the peas happy.
Regularly water peas if the weather is warm. Consistent water will help to prevent yellowing leaves on peas over spring and summer.
6. A lack of sunlight
Peas grown in deep shade can start to develop lighter colored or yellow leaves. Peas will grow best and fastest when they get at least 6 hours of sunlight. This will help the green chlorophyll to develop in their leaves and for flowers and peas to form.
What to do when pea leaves turn yellow
Here are the 3 easy steps to follow if your pea leaves turn yellow to save your plant and get a bigger harvest.
1. Check the soil and water it well
Stick your finger 1-2 inches below the surface of the soil to check the moisture level. Water it regularly every few days for the next 2 weeks. If the soil is too wet, add mulch and allow 2-3 days for the soil to dry out.
2. Add some pelleted chicken manure
Add a handful of pelleted chicken manure around your pea plants to give them an extra nutrient and nitrogen boost. Water it in well to help the plant to recover fast.
3. Move potted pea plants into the sun
If your plants are in deep shade, move the pots into a sunny position. They will develop greener leaves and more flowers to give you plenty of peas over the winter season.
For more on how to grow peas and prevent pests, check out the video below.
Yellow leaves on peas | Summary
Yellow leaves on pea plants can be trimmed off to tidy up the plant once you work out what is causing the problem. Peas are hardy and will recover once they are given the nutrients and water they need.
Peas can struggle whey they are transplanted from a pot to the ground. They will grow much better if they are grown by seed directly in place. If you are transplanting seedlings, do this in the early morning and water them in well so they don’t dry out.
Happy gardening.
I am an accredited practicing dietitian, experienced gardener and a dedicated cook. I love writing and sharing my experience so you can learn from my successes and mistakes.