Smaller Spinach, Bigger Yields: Growing Baby Spinach in a Modular Vertical Farm
Growing baby spinach come with multiple benefits such as more harvest cycles, a more marketable product, and no chance of bolting.
Growcer experiments with baby spinach to overcome common spinach-related challenges in a vertical farm.
Spinach is well known and loved for its nutritional value that’s rich in iron, vitamin C and E, potassium and magnesium. As good as it is on the plate, spinach comes with a few unique growing challenges.
Typically, growing spinach in a vertical farm means irregular, low germination rates and bolting (which is flowering too soon, and dreaded by growers of all kinds). Lower germination rates and bolting reduce the available yield and quality of spinach.
In a previous post, Growcer’s R&D team shared the various experiments conducted to boost germination and reduce bolting in spinach. However, like the true scientists they are, they did not stop there. How can we improve germination, reduce bolting, and improve yields even further?
Baby Spinach Trials
Why
Growcer’s R&D team sought to develop a spinach production system that:
Reduces the challenges seen with spinach production
Increases spinach yields
How
The game plan was to experiment with growing baby spinach. This differs from adult spinach in two ways:
1.Baby spinach has a higher planting density (more crops in less space because the plant is smaller!)
What this looks like is increasing the plant density from 64.6 plants/m^2 to 1,458 plants/m^2.
The higher density was achieved by swapping growing rafts for blocks that had more planting slots, closer together. For comparison, Growcer’s normal growing rafts are big with 32 planting slots whereas the new rafts are almost half the size with 308 planting slots. Remember: baby spinach doesn’t need that much room to grow so it could handle the higher plant density of the new rafts.
Baby greens take less time to mature and have more harvest cycles than their adult counterparts.
The spinach variety Sunangel grown as baby spinach.
2. Baby spinach has more frequent harvests because you can harvest earlier when the crop is younger (faster harvest times = more harvests = more yield)
The harvest time decreased to three weeks from five weeks. With adult spinach, plants spent two weeks in the seedling area. For baby spinach, the use of the seedling area is eliminated.
Baby spinach is seeded directly into blocks, the seeded blocks are packed into bags, and then the blocks are stacked for three days until they are ready to be put in the main growing area.
Typically, you transplant a seedling into the main growing area, but this step is also eliminated for baby spinach. The baby spinach blocks can simply be placed into the cultivation area directly. This - the act of putting the blocks directly into the main growing area - is called “floating.”
Then once the baby spinach blocks are in the cultivation area, it takes three weeks for the plants to mature for harvest.
Harvest Time Reduction
Adult spinach = 5 weeks (+2 weeks of seedling time) to harvest
↓
Baby spinach = 3 weeks (+3 days of seedling time) to harvest
Bonus: Smaller spinach leaves tend to be more tender and have a more pronounced flavour compared to adult spinach, which makes them perfect to eat uncooked in salads and pastas! Baby spinach is also more marketable and in-demand than its adult counterpart.
An example of the normal growing rafts used for adult spinach.
Redesigning the Production Process
As you can imagine, growing adult spinach spaced out (in space and time) is different from growing baby spinach in less space and time. The R&D team discovered that the cultivation of baby spinach - especially at a high density - would require a complete redesign of the production process.
Changes made to suit baby spinach production
Changing the growing rafts
Instead of a big, plastic raft with 32 planting slots, a smaller “block” with 308 planting slots was used instead.
Changing the substrate
Now that we have new blocks for baby spinach, we also need a new substrate for the seeds to be placed in. For the older rafts, we would use rockwool cubes as a substrate, but those do not fit the new planting blocks. For baby spinach, a loose organic substrate was used that could fit into the smaller seedling slots. With rockwool, it’s like fitting a square peg into a round hole, but with loose substrate - you can fill the round hole (seeding slot) much easier.
Determining the optimal substrate moisture range for germination
It sounds like a mouthful, but stay with me here. For adult spinach, the seedlings would sit in a seedling area that would make use of ebb and flow hydroponics. Which is a fancy way of saying the seedlings’ roots would be flooded occasionally with water. However, if you remember from above, the baby spinach does not spend any time in the seedling area.
Instead the seedlings are put in the blocks directly, then into bags, then stacked for three days until they’re ready to float in the growing area. So the R&D team has to figure out, how wet (optimal moisture) can the environment be (specifically the growing medium/substrate the seeds were in) to allow for germination (that wonderful moment when a leaf sprouts from a seedling).
Baby spinach is grown in blocks using loose substrate.
Adding a tool to prime the substrate for seeding
Growcer’s R&D designed a custom dibbling tool to compress the loose substrate before seeding.
Loose substrate is great because it can fit into the tiny holes of the new growing blocks. But it’s also, well, loose. Growcer’s R&D designed a custom dibbling tool to compress the loose substrate before seeding. A proper environment for seeds would also ensure good germination and seedling development.
Adding an “incubation” phase
The seedling area is not used in baby spinach production, so an “incubation” phase was created by stacking the germinating seedlings in a high humidity environment and not exposing them to any light (most of the seeds germinate best in dark environments). The incubation period was three days instead of the two weeks you can expect with adult spinach in the regular seedling area.
“Floating” instead of transplanting
Transplanting is the act of moving germinated seedlings from the seedling area into the growing racks (main growing area). This step is completely removed in baby spinach production because you simply “float” the seeded blocks directly on the growing runways in the main growing area. Who doesn’t love saving time?
For regular sized greens, this is what a typical seeding set up looks like. The seeded cubes then get transplanted to the main growing area after two weeks in the seedling area.
Harvesting in new ways
You might think smaller plants, harder to harvest right? Thankfully that’s not the case. The R&D team uncovered a way to harvest tons of baby spinach using a powered hand tool that acts like a hair clipper. It’s just like mowing the lawn!
Creating new Standard Operating Procedures
At Growcer, we create Standard Operating Procedures (SOPs) that are Team R&D’s recommendation for the best (and most efficient) way to do something in your vertical farm. We have SOPs for everything from harvesting crops to simple maintenance tasks like calibrating your sensors. With a new crop like baby spinach being added to the mix, team R&D also created SOPs so any grower in our network could test out baby spinach production for themselves.
An example of how to harvest baby greens.
Stay tuned
In a few days, we’ll go in depth about how well the baby spinach germinated and yielded with the revised production methods . . . [Update: Read the baby spinach yield results now.]
Did you know? Add baby spinach production to your mix
Are you a current Growcer grower? You too can try your hand at growing baby spinach. Contact your Growcer support representative for more information about the baby spinach upgrade.