Microgreens Harvest #2: Salad Mix Surprises with Higher Single Bar Yields

We’ve decided to start a new series at Aelius headquarters and thought we’d share our experience with all of you. Microgreens have grown in popularity over the past decade, and we saw this as the perfect way to bring some fresh greenery into the office while giving our team a new challenge. The Aelius Grow-Off is designed to showcase how we prepare and grow our seeds, the techniques we use, the products that support us, and of course, the fixture and spectrum used. This harvest focused on a salad mix microgreens trial, comparing growth under two different setups: a single-bar versus a double-bar of our 20W tube lights with our microgreens spectrum with far-red.

In controlled environment agriculture, it’s often assumed that more light equals more growth but this experiment (along with a supporting pea shoot trial) revealed something very different. Our findings suggest that light distribution and crop response can outweigh sheer light intensity when it comes to yield.

Salad Mix Microgreens: Single Bar

Observations

• At Day 4, growth looked healthy and full, although the sunflowers struggled to shed their seed shells.
• By Day 7, the peas and sunflower growth had surged exponentially, creating a noticeably stronger tray than just days before.
• Comparison insight: While it can be difficult to determine yield by visuals alone, this tray appeared denser and more balanced compared to the double-bar trial.
• Yield was the highest of the two setups, despite receiving less light.

Salad Mix Microgreens: Double Bar

Observations

• At Day 4, growth looked healthy, but sunflower struggled to shed seed shells.
• By Day 7, growth was slower, unbalanced, and uneven across the tray, with the right side of the tray significantly shorter.
• The uneven growth suggests that light distribution and uniformity play as much of a role as intensity.

Methods: Aelius Microgreens Experiment

Materials Used

• Microgreens trays (nesting trays with drainage)
• Potting mix/soil (Pro Mix Soil)
• Spray mister
• Flat object for leveling/compacting (we used an Aelius LED driver 😜)
• Bricks for stacking weight
• Cold water
• Paint strainer bag
• Aelius LED 20W Tube Lights
• Salad mix seeds—we got ours from Mumm’s Sprouting!

Steps Followed

1. Weigh & Presoak

• Weighed out 275g of seed for each tray (x2 total).
• Place seeds into a paint strainer bag and submerged in cold water for 10 hours.
• Drained and allowed the seeds to briefly dry before seeding.

2. Prepare Trays

• Even layer of Pro Mix Soil added to trays.
• Compacted the surface with a flat object to ensure uniform depth.
• Misted evenly until moist (not soggy).

3. Seed

• Evenly spread soaked seeds across the trays.
• Pressed lightly into the soil for good seed-to-soil contact.
• Misted again after seeding.

4. Stack and Germinate

• Placed seeded trays under empty trays with bricks as weight on top.
• Kept stacked for 4 days in darkness, misting once daily.

5. Aelius LED Tube Lights

• After stacking, we placed the trays under the Aelius LED 20W Tube Lights (far-red spectrum) with a 16:8 light cycle.
• Watered the bottom tray once a day for 8 days.

Harvest Day Comparisons

Single bar tray: Even canopy, taller growth, highest yields with 424.5g.

Double bar tray: Uneven canopy, slanted growth, slightly lower yield (421.9g).

---

Supporting Experiment: Pea Shoots Microgreens Harvest

In earlier experiments with pea shoots microgreens, we observed the same pattern: more light intensity did not always lead to more yield.

Pea Microgreens Harvest Results (in grams):

• 5000k (Double Bar): 166g
• 5000k + RD (Double Bar): 246g
• 6500k (Double Bar): 169g
• 6500k (Single Bar): 209g
• 5000k + Red (Single Bar): 316g (highest yield & nicest canopy)
• 5000k (Single Bar): 172g

The 5000k + red single bar tray produced the highest yield (316g) and had the most visually appealing, balanced canopy. Meanwhile, double-bar setups such as 5000k (166g) and 6500k (169g) produced significantly less, despite having more light.

---

Final Key Takeaway

The trial confirmed that more light does not always lead to higher yield, a point Aelius has emphasized many times in the past. In fact, the single bar setup outperformed the double bar in both weight and canopy uniformity. Our theory is that excess light stressed the crops, leading to weaker growth.

This experiment reinforces a key point for microgreen production: uniform distribution and crop response matter more than light intensity—anyone can growth microgreens.😉

Comment below which crop you would like to see us grow next!