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If you’ve been following along, you know that we extensively use container gardening techniques here in Alaska. In our cold climate and cold soils, this is a highly beneficial way to improve the results of virtually all warm weather crops. Historically, we have employed the use of fabric grow bags. This year, though, Frosty Garden is moving into sub-irrigated planters and we are excited to tell the story.
We’d like to share with our readers what we are using and why we chose to go this route.
What’s A Sub Irrigated Planter?
If you’ve ever “bottom watered” a plant, you’ve practiced sub irrigation. Sub irrigation has been around for a long time, even the Hanging Gardens of Babylon were based on the concept.
The underlying concept behind sub irrigated systems is pretty simple. You have a reservoir of water that is in constant contact with the container’s soil, typically at the bottom of the container. Your soil will naturally wick water from that reservoir, keeping an even moisture level throughout the soil in the container. As water is absorbed by the plant, the reservoir of water will continually replenish the soil’s moisture.
This might be counter-intuitive to some. You may have had an experience where a pot without any holes became water logged and the plant suffered or died. The “trick” with sub-irrigation is that it will feature an “air gap” between the level of the water and the soil. That gap is usually maintained by some sort of drain in the container. This prevents the pot from becoming water logged, thereby preventing the plant from drowning.
Sub irrigated systems are sort of a blend between traditional soil gardening and hydroponics. Instead of inert media used in hydroponics, you’re using soil instead. Instead of purely liquid nutrients in hydroponics, you might rely on compost or traditional fertilizers. You can also treat them like you would a hydroponic system, which allows you to worry less about the nutritional health of the soil.
Why Did We Need To Make A Change?
Container planting has always been part of our gardening strategy in Alaska. We did a side-by-side trial in 2016 of every variety of pepper and tomato we grew outdoors, in both containers and raised beds. It wasn’t even a contest, the containers won by far. The soil in Alaska is just too cold, even in a raised bed, for plants like tomatoes and peppers to thrive. Putting these plants into containers allows the soil to warm more quickly and we get much improved results.
As we’ve grown our gardens at our off-grid homestead, we have struggled with water utilization. While we have a rain water catchment system, almost any kind of garden will place a significant demand on your water systems. We can’t just make it rain whenever we need water. Our home water is extremely expensive since it’s trucked to our home on a bi-weekly basis. We try to avoid using that for our gardens as it significantly raises the cost of gardening for us.
One of the biggest disadvantages of traditional container planting is inefficient use of water, especially when using fabric based grow bags. Not only do you experience evaporation and overspray when you’re watering, it’s impossible to avoid a fair amount of water being wasted and draining right through the container.
Sub irrigated watering systems have some huge advantages when it comes to water utilization. They eliminate most of the water evaporation that occurs because the water isn’t directly exposed to the atmosphere. More importantly, they are less inclined to dry out, meaning your plants have a continual supply of water and will ultimately produce better. Even more important for us, they result in nearly 100% utilization of the water that you do use.
Choosing The Right Container Garden:
We knew that we had a need to solve our water utilization challenges. Our container and raised bed gardens had grown to the point where it was demanding a fair bit of water. There were a couple of times where our rain water catchment was not sufficient and we had to resort to expensive home water.
We considered a few different options that we knew would be sure fire ways to increase our water utilization. Number one on that list was sub-irrigated planters, but hydroponic systems were also under consideration. There were a few products out there commercially and many DIY solutions.
I saw a Kickstarter last year for a product called the GroBucket, from a small company named Low Tech Engineering, LLC. It was basically a kit that could easily turn a standard bucket into a sub-irrigated container. I noticed that this year the product was available on Amazon.
The more research I did, the more I liked the solution. They had really thought it through. They presented a product that would fit the average person that wants a small container garden. But, they also made sure it scaled to someone like me, that would operate a larger container garden. As I considered the other options, the GroBucket became the obvious choice for an initial trial.
What About DIY Sub Irrigated Containers?
We generally like to pursue DIY solutions here at Frosty Garden. When they make sense. We are all about DIY here at Frosty Garden, but in this particular case, it didn’t make as much sense.
There have been DIY versions of sub irrigated planters out there for ages. Commonly based on 5 gallon buckets, many people have put together DIY versions of sub irrigated planters using various methods.
Every DIY solution we looked at penciled out to $10+ per grow site for us, requiring two buckets plus other parts. It would also take 60+ hours of preparing the 30 or so buckets we wanted to start with. For a few dollars more, we saved dozens of hours of work when compared against the GroBuckets.
We also need to store the entire system of 30+ buckets for half of the year. The DIY solutions had several parts and needed to be broken down for storage. The GroBucket system was designed to be stackable and it took up comparatively less space.
Sometimes commercial solutions are the better option and that was apparent in this case.
What About Alaska Grow Buckets?
Ah, you’ve been paying attention to sub-irrigation 101! The Alaska Grow Buckets are a similar sub irrigated system, designed by Jim Lister of Wasilla, Alaska. All ready a hometown favorite.
These were seriously under evaluation and may still have have a future home at Frosty Garden’s homestead. Or, perhaps a hybrid approach with GroBucket sub irrigation hardware.
The real problem for us with the design was sourcing sufficient quantities of appropriate colanders that could be used. We weren’t able to locate super cheap colanders here in Fairbanks and Amazon wants $8-$10 for almost any colander. There’s also the matter of sourcing shopping bags, again for 30+ buckets. A few dollars here and a few dollars there and you might be spending more time and money than a commercial solution.
With DIY, there’s an issue of repeat-ability. It’s fine to be able to one off something with used materials and it’s awesome when you can get it to work. But, when you’re trying to make 30+ of something, you often will need to source the materials unless for some reason you have them all on hand.
What I do really like about the Alaska Grow Buckets is the solution for root air pruning. The holes in the side of the bucket are genius, taking a sub irrigated bucket into the same realm of fabric grow bags. It literally could be the best solution out there.
I hope to eventually do a little bit of a trial with one or two of our GroBuckets having these holes for comparison sake. As long as the modification doesn’t interfere with bucket nesting/storage, I suspect this may provide for great plant improvement with only marginal increase to water evaporation.
Why Not Go With Hydroponics?
I’ll admit that I was a little bit excited to get back into a hydroponic system again.
I primarily considered the Dutch Bucket system of hydroponics. This is a recirculating/drip system that does really well with larger plants such as tomatoes, peppers and many other larger plants.
Three factors worked against this decision, though.
The first, and most important for us, was that our container garden was in flux. We currently have our container garden on our deck, but eventually we’ll expand into a greenhouse and relatively dedicated space. This meant I’d have to re-tool the hydro system at some point in the future, which meant doing things twice.
The second is that the dutch bucket system isn’t very mobile. I really enjoy the flexibility of moving my container garden around as necessary. I don’t need to think about plant spacing as I can just move the containers where I need them. A dutch bucket system is far more rigid in its design and doesn’t offer flexibility.
Lastly, the GroBuckets were more flexible. They could accommodate virtually any plant, from herbs to potatoes to large warm climate crops. A hydroponic system is usually a one-trick pony and different systems are better at certain kinds of plants.
Eventually we’ll get a hydroponic system running, but it’s not our current priority.
Doing The Math On GroBuckets:
When we do projects like this here at Frosty Garden, we try to do a general cost analysis on it to figure out if it’s worth it. We also value a certain cost of learning, so we’re also not adverse to trying new things just to see if and how it works.
There are three major things at play when you’re looking at something like the GroBucket investment.
- Initial investment cost
- Operational cost
- Value received.
Our primary motivation was to save on operational cost in this case. Water is expensive for us, so we want to reduce what we use. But, if we could also increase yields, that also increases the value we received.
Here’s how the math pencils out for us, just in water usage alone. We assign a cost of water to be about 10 cents per gallon. Rain water obviously doesn’t cost us that much, but our home water does. Therefore, our rain water has equal value to our delivered home water.
The total cost per grow site will be about $15 between the bucket itself and each GroBucket unit. Using fabric grow bags, I estimate we lose better than 50% of water used to loss through draining out of the container, overspray and evaporation. If a plant uses 50 gallons of water over its lifespan, that means we had to apply 100 gallons over the course of it’s life. Multiply that by 30 sites, that’s about 1,500 gallons of water wasted over a year.
For us, that waste costs $150, since that water has a value to us of 10 cents per gallon. So, in 2 years, we will have paid for the system entirely, and that’s without even considering the value of the produce we’re growing. That’s a pretty good return on investment in my book.
If the product results in improved growing conditions, which we suspect it will, it will also increase the value of what we’re growing. If we can achieve higher yields, that will also increase value back to us.
Sub Irrigation Solves Common Garden Problems:
The Grobucket will solve problems for us. I’ve found that due our limitations in water, I’ve been “too stingy” with watering. It’s always better to water more thoroughly but less often than it is to water less thoroughly and more often. Despite knowing this, I think when you’re in our situation with limited water it’s only natural to hold back. We’ve experienced tomato and pepper cracking due to insufficient watering, so the GroBucket system should help improve our yields of quality fruit as well.
If you’ve ever grown plants in containers, you know it can be difficult to keep up with watering. During hot periods, especially in the late season, you might have to water your plants twice a day. Containers can dry out quickly since there is no contact with other moist soil. The GroBucket reservoir of water will ensure that there is sufficient water and it will also let me know when the supply is running dangerously low.
What I’m really looking forward to is less work in the garden overall. Between our community garden and home gardens, we sometimes spend 2-3 hours a day watering on the hot days. This process should be more streamlined and I expect it to shave off almost an hour of watering each time. We should also have to water less frequently, I am hoping to get 2-7 days per watering cycle. As we’ve increased our gardening efforts every year, we’ve had to look at ways to streamline existing processes and the GroBucket is one of those efforts.
The Future Of GroBuckets At FrostyGarden?
While we intend to primarily grow our tomatoes and peppers in these buckets, we should have a few spare buckets that we need to put to work. We will likely do a trial of some things just to see how they do. We will likely see an herb bucket or two and maybe some brassicas or artichokes to compare them against our community garden.
I am sure we will have an update once we get plants in the system, but I’m a solid believer in sub irrigated systems and am excited to give these a try. I am hopeful that the GroBuckets can get me a level of simple, low tech automation that is desperately needed.
This could also be the tech that allows us to bring our entire garden to the house, and that’s exciting. Our current gardening needs well exceed our home’s water capacity, so we continue to use our community garden primarily for the access to unlimited water. If these work as well as I hope, I could easily see 100+ of these growing our brassicas, artichokes, squash and even potatoes. It also wouldn’t be difficult to set up a central water barrel for even easier automation. I have a dream of a garden that you just have to prepare and harvest, with minimal work in between.
2019 Season Update:
We couldn’t have been more pleased with the GroBucket system. The system will be expanded to cover our entire container garden, as well as to fill out a greenhouse we are building in 2020.
More to come, we’ll link back here when the full review is ready.