What to grow in a vertical farm: R&D Recommended
Find out why we recommend you grow these specific leafy greens in a vertical farm.
The Why
The vertical farming industry is currently geared towards producing leafy green vegetables, but why? From what makes the most sense financially, to the characteristics of leafy green vegetables themselves, there are a few good reasons why lettuces, herbs, and the like are the gold standard for hydroponic crops.
A shorter supply chain (made possible by localized production) is more noticeable in crops like leafy greens compared to other crops like root vegetables.
Ultimately, these crops are usually fast and easy to grow at reliable volumes while giving you the most return on investment.
For your customers, locally grown greens are superior to imported ones because leafy greens don’t keep well. You’ve seen wilted leaves on grocery store shelves right? Or even in your fridge when you forget to make that salad . . .
A shorter supply chain (made possible by localized production) is more noticeable in crops like leafy greens compared to other crops like root vegetables. We hear it all the time from growers - their customers marvel at how long their Growcer-grown produce lasts and praise its superior shelf life.
Even within leafy greens, Growcer’s R&D team has preferences on which varieties we like to grow because of how our Osiris farm is set up. Yes - small differences can make a big impact.
Keep reading to understand which leafy greens R&D reign supreme and grow best in Growcer farms, and why.
The What
Since October 2020, R&D investigated a wide range of crops in the leafy greens category to see what grows best in Growcer’s Osiris farm.
It’s important for us to study yields using our particular farm set up because not all modular farms are the same. Some farms are built in containers and some farms use different types of hydroponic growing methods.
By growing plants in a replica of one of our customer’s farms, we can better assure you of the quality and yields you can expect in your own farm.
Characteristics of crops that grow well
Relatively low growing height
Growcer grows plants horizontally, meaning horizontal grow racks are stacked on top of each other instead of in vertical grow towers.
Because the growing racks are stacked on top of each other, there is only a certain amount of vertical space for plants to grow tall - approximately 15.25” from rack to lights. For crops to grow well, a relatively short growing height is a requirement.
If it’s a tall crop it will grow into the light (and get burned) or be stifled because it has nowhere to grow.
Conversely, in vertically oriented racks, growers face the same issue. Except instead of running out of room, plants (used to growing up instead of sideways) don’t have the stem strength to support excessively large growth and can break off easily, causing harvest losses.
Because the growing racks are stacked on top of each other, there is only a certain amount of vertical space for plants to grow tall. For crops to grow well, a relatively short growing height is a requirement.
Shallow root system
Growcer uses deep water culture hydroponics, but we’ve nicknamed our style of growing “shallow water culture,” because the plants sit in a shallow pond of water.
If a plant has an extensive root system, it can clog the shallow pond of water or have limited uptake of nutrients. It’s very similar to how you have to re-pot house plants so they have enough room to grow.
If you have crops with extensive root systems, they might outgrow the system before they reach full maturity.
For example, herbs grow in our farms for a maximum of 12 weeks and at their end point, the root systems are very thick, dense, and interconnected. Thankfully, we harvest them fully at this point and there’s more room to replant the next crop. If the roots were to grow to this level in 4 weeks - then the crop wouldn’t reach its full potential and that’s why a shallow root system is preferred.
Root vegetables, such as carrots grow best in substrate such as soil, and generally they need the space to grow downwards, rather than just laterally.
Short growth schedule and quick turnaround time
Space limitations above and below “ground” (or rack in this case) mean it’s best to grow crops with a fast growth schedule. Growcer focuses on crops that grow in 6 to 12 weeks so you can be consistently harvesting (and consistently selling or distributing).
Sure, it’s possible to grow crops that take longer to grow, but consider that during this longer growth period you also need to pay to keep the lights on, so to speak. Wouldn’t you rather get more harvests in a year than less?
Enjoys having water and nutrient solution available at all times
The plants we grow are sitting in a nutrient solution 24/7. This offers great stability because we know the plants won't dry out. However, not all plants like 24/7 access to nutrients and water.
For example, strawberries do not tend to like being wet all the time. Strawberries prefer to be irrigated, have time to dry out, and then repeat.
In contrast, the crops we grow thrive under consistent irrigation and tend to dry if they are not regularly and frequently watered. It’s all about picking the best plants for the environment you have.
Thrives under generalized environmental and nutritive conditions
Stay with us here - it’s not as complicated as it sounds.
Despite leafy greens sharing quite a few similarities, each crop also has very specific preferences for their environment (i.e. temperature, photoperiod, light intensity, etc.) and nutrition (EC, pH, specific nutrient quantities, etc.). It’s not one-size-fits-all, even for leafy greens.
For example, some greens can tolerate a temperature greater than 25°C whereas others, like spinach, prefer temperatures below 20°C. Spinach is a cold-weather crop but is able to meet other greens in the middle with a standard daytime temperature of 22°C.
It’s like having a picky eater. Some crops are way too picky when it comes to their environment and won’t grow. Others are more “chill” and can still thrive in 98% optimized conditions.
The crops that perform best in a Growcer farm are the ones that thrive in a “happy medium” where their environmental and nutrient ranges have more flexibility. This also means that our fave crops play nicely together, meaning you can offer a greater variety of produce, more easily.
The crops that perform best in a Growcer farm are the ones that thrive in a “happy medium” where their environmental and nutrient ranges have more flexibility.
Results
Growcer’s R&D team recommends a specific list of lettuces, asian greens, leafy greens, and herbs based on the characteristics and requirements of these crops (listed above) and based on what we’ve tested ourselves.
Lettuce
| Recommended Variety | Why it made the cut |
|---|---|
| Monte Carlo | This is a romaine lettuce variety and is best selected for its crunchy, crisp texture. We like this variety because it is low growing compared to your typical romaine, so we see little-to-no cases of tip burn.
Why is no tip burn important? Because when the tips of your leaves look burned and shriveled, they’re less appealing to consumers (and therefore less sellable) and have a reduced shelf life. No tip burn = better marketable product. |
| Rex Butterhead | This variety has a softer leaf and is recommended by our seed supplier as a true hydroponic performer. |
| Green Star | We’ve been told by a few visitors to our farm that this variety would look perfect on a hamburger! It has a curled leaf and falls under the ‘green leaf’ category of lettuce. |
| Wildfire | Lettuce or leafy green mixes are also a possibility in the Osiris farm. Wildfire lettuce mix contains 5 different varieties of lettuce in one bag of seed. These varieties are grown and harvested together and can be sold as mixes. |
Spinach
| Recommended Variety | Why it made the cut |
|---|---|
| Space |
Although this variety has a lower yield when compared to other varieties we’ve grown, it is less prone to bolting, making it easier to harvest and therefore reducing labour. Labour is one of the largest expenses when running a vertical farm which is why knowing how long it takes to grow in a farm matters. |
| Sunangel |
Conversely to Space, Sunangel has a greater yield potential but is more prone to bolting. High risk, high reward! Dig deep into Growcer’s spinach trials on reducing bolting and improving germination rates for more. |
And more!
| Crop | Recommended Variety | Why it made the cut |
|---|---|---|
| Choi | Asian Delight | This is more of a condensed variety that is perfect for the standard growing rafts used in the Osiris farm. While other varieties we’ve tested yielded higher, they tend to be a bit more brittle making ‘Asian Delight’ the best overall performer. |
| Kale | Toscano | This is our tried and true variety. It has thickened and very long leaves. It’s one of the toughest crops you can grow, no matter the obstacles, because “kale don’t care.” |
| Arugula | Standard/Sylvetta | A very robust and high yielding cultivar, the Standard has great yields and is resistant to bolting while the gourmet variant Sylvetta is low yielding and easy to bolt, but has spectacular taste (and the flowers are edible!). |
| Basil | Genovese | This variety has a great fragrance and taste (that’s why R&D loves to harvest it so much). It is known to be slow bolting, uniform, and fast-growing. |
| Mint | Common | Simply the best. A slow starter but once it’s established a very prolific producer of the fine herb. |
What doesn’t make the list
Undesirable traits
Certain crops show undesirable traits, such as a tendency to bolt (go to flower and seed which leaves a bitter tasting green). Or they pale in comparison when it comes to flavour or yield. And sometimes it’s their shape - is it compact or elongated - and does it fit our farm’s growing environment best? This doesn’t mean you can’t grow these crops, but it does mean, we as an R&D team won’t recommend them.
Untested varieties
Although we have our favourite varieties, they aren’t the be all and end all of what you can grow. New varieties are constantly being bred with desirable growth traits so we are always on the hunt for the latest and greatest to add to our rotation. They will be in the list of recommended varieties after we’ve had a chance to test them out of course.
Going beyond the list
Recently, we’ve been exploring new ways to grow specific crops more optimally in the Osiris farm. For example, we are looking at new varieties of lettuce and how we can change the current recommended production schedule to improve ROI. Or in other terms, should we leave the lettuce in the seedling area longer? Can we harvest the lettuce from the growing area sooner? Can we reduce the amount of time lettuce needs to mature so you can get more harvests and a higher ROI?
Finally, there are many crops that can be grown in a Growcer farm that aren’t in our recommended list. The R&D team has been trialing crops highly requested or currently grown by our network of customers such as swiss chard, dill, chives, spring onion, and rosemary. We conduct extra research to complement the work customers are already doing as they expand what they grow in their own farms!
Rosemary being grown in a customer farm.
So what? The conclusion.
Grow what you want. We have lots of customers seeing success with a wide variety of crops! Just know that there may be trade offs in yields and reliability. If you’re in a place to experiment, have at it (and let us know how it goes)!
Or grow what we’ve verified you can grow easily, reliably, and at yields that give you a profitable return on investment. If this is your situation, we’ve got you. Our R&D team exists to make sure that we do the research so that you can focus on growing and bringing local produce to market and to your community.