Speckled Pea Microgreen Seed

Pea shoots are a favorite starter crop for new microgreens growers and often a best seller for more experienced growers. There are multiple varieties to choose from, so you will need to learn which ones work best for your growing system and customer base. Peas do well in both cool and warm conditions, but are not a fan of the heat which can suppress growth.

Microgreen Soil

Like most microgreens, pea shoots benefit from a well-drained, nutritious soil consisting of:

• Peat or coir for rooting and holding water (75%)
• Perlite or vermiculite for drainage and aeration (20%)
• Small amount of high-quality compost for nutrition (5%)
• Lime to neutralize pH

Many sources state that microgreens do not need nutrients to grow as they have “all the nutrients they need already in the seed”. Our experience is that microgreens grow better with additional soil nutrients, which can be provided with a small amount of compost in your soil mix. Good-quality compost also adds microbial life which can help reduce crop disease. However, too much compost, especially nutrient-rich compost like worm castings, can result in surface mold and reduced water uptake due to nutrient salt content.

Sanitizing Microgreen Seeds

Sanitizing your pea seeds before sowing helps reduce the likelihood of human pathogens in your crop. Seed can be sanitized before or after soaking - or both. Zerotol is a peracetic acid based sanitizer which is approved for organic use in Canada and the United States.

Pea seed should be sanitized using the immersion method, where the seed is soaked in sanitizer before sowing.

Seed Soaking

Soaking in water induces germination in large seeds like peas. Rinse seeds well before soaking to remove any loose debris on the seed. Pea does well with a 12-hour or overnight soak.

Sowing Microgreen Seed

Sow pea seeds using the “dump and spread” method:

• Measure out the desired volume of wet seed needed to sow a tray
• Dump the seed in the middle of the tray
• Spread the seed evenly around the tray using your hands

This method can feel clumsy at first, but most growers establish a good technique for quickly and evenly spreading the seed. Even seed distribution is crucial for uniform crop growth. Avoid bare spots and seed clumping. Pea seeds roll! So be careful not to spill too many off the sides of your trays.

Germination

The germination stage can set the crop up for success or failure. Poor germination can be difficult to recover from, so optimizing germination conditions is crucial for crop success.

Pea shoots germinate well in the lower range of 72°F to 79°F (22°C to 26°C).

Stacking Sowed Trays

Pea shoots do well when “stacked” during germination, where trays are stacked one on top of the other.

For stacking pea shoots:

• Stack to a maximum of 3 trays high to prevent toppling. Also reduces pressure on the bottom tray
• Top the stack with an empty tray and a 14-lb concrete paver

The top tray will have slightly taller growth than the bottom tray, but come harvest time they will almost completely even out (see images below).

Uncovering Pea Shoots

Pea shoots should be removed from the germination stage when the shoots are about one-inch tall and clearly pushing up the cover tray on top of it.

Water pea shoots thoroughly from above when removing them from the germination stage and moving them to the light.

Peas do not recover well from wilt, so make sure they are always well watered.

Peas ready to be uncovered: https://photos.app.goo.gl/eqB9grSPNy6uMM3Q6

• There are two indications these peas are ready to be uncovered. The first is the germinating peas pushing up the 14-lb covering tray. The second is the longer shoots poking out the sides. Shoots trying to “escape” are a great indicator for when to uncover.

Lighting

Pea shoots thrive in 14 to 16 hours of light at 5000K to 6500K, or in natural light. If using LED or fluorescent lights, keep them close enough to the crop to prevent stretching. How close will depend on the intensity of your lights.

Online information shows a wide range of optimum PPFD values for microgreens production, ranging from 50 to 400 (Liu et al., 2022; MechaTronix, 2023) We have had success with PPFD values as low as 25.

Overhead Watering

Pea shoots are one of the few crops that thrive when watered from above. Overhead watering is best done with a watering wand on the shower setting. Try to find a wand with flow control so you can lighten the shower if you have high water pressure which will reduce the likelihood of knocking the crop over during water.

If the soil is very dry, give the crop several light passes to allow the soil to rehydrate and avoid runoff. Dry soil becomes hydrophobic and will repel water or cause it to run right through (or over) the soil.

Bottom Watering

Many growers like to water their crops using the “flood” method, allowing the soil to absorb water from below instead of from above. This method keeps the crop dry, which can reduce disease pressure and make for easier harvesting. Place a solid tray below your growing tray and fill that solid tray with water. How much water you add will depend on how dry the crop is and takes some time to master. Do not overwater as waterlogged (saturated) soil is at higher risk of contributing to crop disease.

Pea shoots can use a lot of water so prepare to water them daily in warm conditions and often twice daily in hot conditions. Pea shoots are a good candidate for overhead watering as the leaves shed water well, but do not water overhead in the last 24 hours before harvest to keep the leaves as dry as possible.

Harvesting Pea Shoots

Pea is an easy crop to harvest and process. By keeping pea leaves dry in the last 24 hours of growth they can be harvested and placed right into their packaging.

Cut pea shoots close to the base of the stem with a sharp, good-quality knife. Do not use scissors as this will tear the base of the stem and reduce storage time. Radish does not have a firm stem, so be gentle when cutting. Cut small sections at a time with a quick motion with the knife to ensure a good quality cut.

If the crop is overmature it will get fibrous and inedible - starting from the base up. If the crop gets overmature, you can cut it higher to avoid the fibrous part.

Packaging

For retail locations, growers typically use a clamshell for optimizing both display and storage. For bulk packaging options, you can use roll bags or reusable containers.

Storing Pea Shoots

Like most microgreens crops, pea shoots should be kept dry and stored in a fridge between (2° to 4° C or 25° to 39° F) at all times. Be sure to maintain the cold chain during transport by using coolers with ice or a refrigerated vehicle.

Modern Grower Research

At Modern Grower we are constantly doing microgreens trials to better understand crop growth characteristics in varying conditions. All the data we provide is informed by our research.

Check out our ongoing research here to get a better understanding of the crop.