Thursday, December 22, 2011
This video will show how the exterior of the dome is covered. The northern face of the dome has no polycarbonate and is covered in OSB and will eventually be shingled. Each of the triangle sections needs to have studs added to support the boards. Placing them can be tricky when it’s difficult to reach all the points.
Sometimes the best laid plans don’t always work…
Once all the studs are installed, it’s time to install the OSB. I found it was easier to set the sheathing by ripping the OSB into two foot strips instead of leaving them 4 feet wide. It also reduced the amount of scrap that was generated.
The shed roof and part of the dome are covered in water and ice shield. This will protect the building during the winter and will allow me to shingle the roof in warmer weather. The shielding has an adhesive backing which helps to hold it down to the OSB and a few roofing nails insures a gust of wind won’t peel it off.
The polycarbonate sheets are 6 by 24 feet long. I set up a couple of sacrificial sheets of OSB on the ground as a cutting area.
I decided to repurpose an old tape measure and cut it up so I could easily measure out the various leg lengths for the triangles. With a couple of clamps to hold the ends, it made it easy to triangulate all the points. I found it was easier to make my marks by just poking a nail through the material. Trying to mark the frozen poly with a frozen Sharpie was a futile effort.
The polycarbonate cuts very easily with a sharp circular saw. After I filmed this, I discovered it was even easier if I placed another scrap piece of polycarbonate under it so the blade didn’t have to also cut into the OSB.
Setting up a guide allows for a nice straight cut. After each piece is cut, the protective film can be removed and the sawdust in the flutes is blown out with compressed air.
Installing the panels was quite simple providing there was no wind. Before cutting each panel, I did measure each opening to insure the measurements matched the computer calculations. There were a couple of sections that were slightly off which was probably from slight errors in the hub construction or the strut measurements. But, for the most part they all went in as planned.
Each panel was cut so that the flutes are orientated to allow for condensation to drain out.
Once I got down to the ground level, it was even easier to install each section. All the panels are held in place with stainless steel screws that have a neoprene-backed washer. The screws pierce right through the polycarbonate and the washer creates a watertight seal against it.
All the joints will be taped in the spring since the waterproof tape needs to be applied when it’s over 60 degrees. During this filming it was 20 out. You may have noticed that I’m wearing insulated boots, long-johns, a sweatshirt, insulated hoodie sweatshirt, scarf, winter coat, winter hat under the hoodie, and insulated gloves!
All the panels intersect nicely over the hubs. The original plan of rabbiting each stud so that the panels wouldn’t interfere with the bolts worked out well. Also adding the bevel to the studs made a large flat surface for the panel to rest against.
The panels along the base are cut extra-long so that they will hang over the knee wall. This will help to shed water and prevent it from getting into the dome through the knee wall. The overlapping pieces are simply cut off with a razor knife.
The northern face of the dome that isn’t covered by the shed was also studded and covered with OSB. Unfortunately, my HD camera was broken so I wasn’t able to film this part, but this is what the final construction looked like.
When I laid out the building, I oriented it so it faced due-south. It now acts like a huge sundial and it’s very easy to tell when it’s time for lunch!
That’s it for now. Next up may be the heating system. It’s getting difficult to work in the freezing temperatures! Don’t forget to join our Facebook page!
This phenomenon is called “needle ice” and it occurs when the soil temperature is above freezing and the air goes below freezing. The water in the soil is drawn out by the cold air and quickly freezes, building these long strands of ice. They’re also fun to crush!
Monday, December 19, 2011
Sunday, December 11, 2011
Here's the next teaser video on the dome project. All is going well. I'm still scrambling to get the building enclosed before winter set in. It's getting challenging working in this weather...everything is frozen in the morning, then barely thaws during the day, making it wet and slippery.
Sunday, November 27, 2011
Once again you’re treated to an extra-long video about building the dome!
The structure went up in a day! I started off the morning by laying out all the pieces around the perimeter knee-wall and bolting everything
together. This helped to create a firm base to build on.
A fellow aquaponic grower and dome lover, Steve, volunteered to help erect the dome. This was one job where having an extra set of hands was
extremely helpful. We found it was easiest to connect two legs together with a hub, and then set them into the base unit. When the bolts were placed
in the hubs, each section was able to stand on its own without any supports. Once we figured out a system, the entire assembly process was relatively
A couple of the bolts would get stuck going through the struts, but a little persuasion would get them in. Once each triangle section was installed,
we would connect each one with a horizontal strut. This simple action made the side wall rigid enough to support my weight of leaning against it.
It took a little bit of thought on how to assemble to the second level, but we decided the best way to assemble it was the same way as the first tier:
Steve would support the assembly from the ladder and I would align it with the hub and run the bolt through it.
The horizontal strut was a bit trickier but I was able to lean a ladder against the dome and hold it into place.
The third tier went together just as smoothly. The dome was self-supporting and there was no problem leaning against the structure to assemble the
By the end of the day, the dome was now visible from the road and a few of the neighbors would stop by to see how we were progressing.
We finished late in the evening using flashlights….here is how it looked when it was completed.
Here’s a little time-lapsed segment of the dome being assembled.
On October 30th, we had a freak snowstorm that decimated the region. We were without power for a week while the town and line crews cleaned up the
roads and utilities. The project was put on hold…
Once we recovered from the storm and most of the snow melted, it was time to go back to work. Even though the dome was standing on its own, I stilled
needed to adjust a few of the hubs and tighten the nuts.
The next part of the project was to build the walls for the shed area. One of the biggest problems with working in the fall is the rain and snow,
along with the constant freeze and thaw cycles. This turns any disturbed dirt in to mud. I decided that it was best to build the walls up by the
house and set them in place with the tractor.
When building a prefab-type building, it’s critical to make sure each section is square and accurate. Once each wall frame is squared up, I would
secure it with a few angle braces to keep it from racking. After all of the studs were nailed in place, I would again check to make sure it was still
square and then install the sheathing. Since the walls are placed so close to the ground, I installed treated plywood sheathing along the bottom 16
inches of the wall to help prevent rot and insect damage.
The excess sheathing is marked and cut off to the appropriate length and then nailed into the studs.
My good friend, Ford, helped me lift the walls and carry them to the greenhouse site. Each section fit perfectly into place. Ford was also kind
enough to hold the wall in place while I secured each section together.
After all the walls were in place, I finished installing the remaining sheathing.
Even though the dome structure probably could support the weight of the shed roof, I felt it was best to add a support beam across the length of the
shed and cantilever the rafters over the dome. The rafters are attached to the dome, but they have almost no load bearing weight against it.
There are 35 rafters, all custom cut with the correct angle to match against the dome. Any of the excess is then cut off, and the scrap is then used
as blocking between the rafters to keep them from racking. The roof decking is then laid down, cut, and secured.
Once again, that’s the end of another segment. I invite you to join our Facebook page at the link below for building updates prior to these video
releases. Thanks for watching!
Friday, November 11, 2011
Monday, October 31, 2011
I had too much video to cram into 5 or 6 minutes so you get a double-feature today!
We’ll start with the sump tank that’s located in the center of the dome area. Plastic tanks can’t be buried directly in dirt since they expand and contract with temperature change and the weight of the dirt will eventually crush them. I surrounded the entire tank with scrap 2 by 4’s and built a brick wall around it. When the well was completed, the goal was to simply lift the tank out, remove the boards and set the tank back in the well, resulting in a space between the tank and the well wall.
I didn’t realize that the tank was slightly tapered so the bottom was larger than the top - the tank was trapped inside the well! If you watch carefully, you can see the entire well lift slightly with the tank. Some extra pondering was required…
I decided to slide each board out one at a time until enough were removed to loosen the tank. I drilled part-way through the board, inserted a bolt, wrapped a strap around it, and lifted the board until it hit against the rim of the tank. Then cut the section of board off and repeated the process until the board came out. This was a few hours wasted, but it worked!
There is a larger sump tank that is located in the shed area that also needed a well built around it. This is a cone bottom tank so I tightly strapped some 2 by 4’s as legs to it to keep it level, then set the rest of the spacer boards around it. After leveling out the area, I set some cement blocks on the ground to act as a footing for the brick work. When it was complete, a perfectly round well was surrounding the tank and we were able to pull the tank out with the excavator.
This is the baby brother excavator compared to the one that dug the foundation hole. With a slightly smaller bucket, it was able to place the dirt back into the bottom half of the hole. Bruce, the operator, was very careful and didn’t hit a single block off the wall! When the area was roughly level, he tamped the dirt into place to help prevent future settling.
While Bruce graded around the exterior of the foundation, I set the tubing for the thermal mass. There are 5 equal length perforated pipes that connect to a central manifold which will eventually be connected to a heating system. The tubing zigzags around the floor to help spread the heat evenly throughout the dome. The exhaust for each tube then vents to a different area in the dome.
Six inches of stone was placed around the tubing. This is partly to protect the tubing from larger rocks, and partly to allow some more air flow for heat distribution into the thermal mass floor.
Earlier in the project, I didn’t have time to set the anchor bolts in the foundation wall. To make sure they were placed in the correct locations, I first cut all the treated lumber sill plates to their correct lengths and labeled them. I then drilled a hole for the anchor bolt into each plate, roughly in the center of a one of the block cavities.
The entire cavity didn’t need to be filled with concrete so I filled them half way with stone first. It was a nice day so I got a helper. Her job was to vibrate the air pockets out of the concrete as I shoveled it into the cavity. I then leveled off the area and set the j-bolt into the concrete, and then set the sill plate over the area to make sure the bolt was in the correct location.
This is what happens when you don’t wear boots in a construction area!
There will be an outer ring of grow beds around the perimeter of the dome, and also a central ring. This 2 inch drain pipe will allow the beds to drain into the central sump tank. The piping is temporarily set on bricks to make sure they are sloped in the right direction.
More dirt is filled between the pipe areas and sand is filled around the pipes. This helps to protect them from stone and allows them to be fine-tuned for the proper slope.
Now that all the drain pipes are installed, the sump tank can be dropped into the well. Holes are cut through the side of the tank and the pipes are pushed through the holes. I plan on installing an elbow at the end of each drain to try and swirl the water a bit.
The large sump tank is a bit trickier to install since the cone shape needs to be properly supported. I made a quick template that was equal to the angle of the cone. Sand was then added to the bottom of the well and I used the template as a guide to shape the sand into the same angle as the cone. The tank dropped into place perfectly!
The dome will sit on a 16 inch knee wall. Although each section should match perfectly with the dome, they will be left loose until the dome is assembled so they can be adjusted. Each section is placed on a strip of foam to help prevent air from leaking between the concrete wall and the boards. They are then loosely bolted into place.
That’s it for now. Thanks for watching and don’t forget to join our Facebook page at the link below.
Monday, October 17, 2011
Thursday, October 13, 2011
Monday, September 26, 2011
Tuesday, September 20, 2011
Sunday, September 18, 2011
Thursday, September 1, 2011
Monday, August 22, 2011
Friday, August 19, 2011
It's all in German...they said the article may be picked up by their English counterpart later this year. I have no idea what it says...for all I know, they said I was a raving lunatic!
Saturday, August 6, 2011
Friday, July 29, 2011
Friday, July 22, 2011
I’m a bit overdue with an update on the aquaponic setup in the Harbor Freight greenhouse.
Cucumbers love the heat. These older leaves have some brown spots from aphids but the rest of the vines have grown up into the cross braces and make a really nice canopy area. This year I’m only growing the smaller pickling cukes. They grow fast, produce a lot of fruit, and are resistant to powdery mildew. Last year we had 264 cukes from 2 plants and are on target to have a higher yield this year!
The cherry tomatoes are also doing very well. This one plant has huge clusters that contain about 50 tomatoes each. There are about 250 pieces on this one plant with more areas starting to flower. The clusters have gotten so heavy that I had to tie each one up to the main support line so that they don’t tear themselves off of the stalk.
Last year I grew an heirloom tomato called Brandy Wine. They were huge and delicious, but were prone to cracking and getting mold in the cracks. This year I’m trying Amish Paste tomatoes. I like them much better since they are far smaller and haven’t been cracking.
The vines probably produce the same amount of weight, but there is a higher quantity spread out over time. There are 2 plants in the greenhouse and they are on target to produce 50 tomatoes each.
Each year I grow a couple of bell peppers. They grow well, but don’t produce any more than a few peppers each, which is on par with our regular garden.
This is the second year I’ve tried growing eggplant. They grow well and produce flowers. Then the leaves start turning white and the plants eventually die off. I’m not sure what is cause of it is.
It’s too hot during the summer to grow lettuce so I let this one plant go to seed. It will produce more than enough seeds to use for the fall planting and also for next spring.
The strawberries were also done producing in the spring. They are now sending out runners which I will let them take root, producing more plants for next year. Once I get enough runners, I will start cutting any others back so that the energy will stay in the main plant.
In the original 8-inch tube grow beds, I planted carrots again. This time I’m trying a Danver’s half-long variety instead of the standard length. Hopefully they won’t hit the bottom again!
The automation system is still working well including the 6-way sequencing valve. The automatic fish feeder is also working well with just a few signs of rust. The fish are fed just the right amount based on the water temperature.
Thanks for watching. I’ll leave you with some underwater footage of the fish. Please subscribe to receive updates about future videos!
Saturday, July 16, 2011
Monday, June 20, 2011
I've started to experiment with rocket mass heaters and have had very good luck with running a good clean burn. It will be quite impressive to be able to heat the entire greenhouse without needing electricity to store heat in a thermal mass or run a blower for the burner. More to come!
Friday, June 17, 2011
Click here for project details
Sunday, May 22, 2011
Wednesday, May 4, 2011
Tuesday, April 19, 2011
130 +/- year-old tree. Each tack is 10 years. Where were you in 1880?
Wednesday, April 6, 2011
Friday, March 18, 2011
Bigelow Brook Farm is pleased to announce a new partnership with The Aquaponic Source as a distributor for our expanded shale product line. The Aquaponic Source (www.TheAquaponicSource.com) specializes in a wide array of products providing complete solutions for the North American home aquaponic gardener. Along with their on-line store, they also provide an active and free community site filled with a vast array of aquaponic discussion topics and information for both novice and experienced users at www.AquaponicsCommunity.com. “We are extremely excited to be working with Bigelow Brook Farm and offer expanded shale to the aquaponic and hydroponic gardening communities. Finally there is a US based grow media with optimal growing properties!” says Sylvia Bernstein, President of The Aquaponic Source. “We think this will become a core component in the rapidly expanding soil-less growing market in North America.”
For more information about Expanded Shale, please visit our web site at www.BigelowBrook.com or www.ExpandedShale.com.
Monday, March 14, 2011
Below is the transcript from the video....
This is the third video in the series about building a geodesic dome greenhouse. This time I will cover how to build the interconnecting struts which are made from red cedar. I choose red cedar because it is rot resistant. You could use treated lumber, which is substantially cheaper, but I was concerned about chemicals leaching into the water for my aquaponic system.
The site I used for the calculations is acidome.ru. The entire site is in Russian, but Google Translate does a fairly good job converting the text. The calculator lets you enter the diameter of the dome, choose the hub type and size, and even the dimensions of the struts. It will then calculate the angles needed at each hub and also calculate all the various sized struts and labels them with the dimensions taking into consideration the size of the hubs.
The best feature is the ability to have the software calculate a flat base, since a 3V 3/8th dome is not flat. One click and the struts are recalculated with the proper lengths!
With a 33 foot diameter 3V dome, each triangle will never be wider than 6 feet. This will allow me to purchase the polycarbonate glazing in 6 by 24 foot sheets, helping to minimize the amount of scrap.
The struts are made from red cedar 2x4’s by 14 feet. This will be enough material to cut 2 struts from each board with some scrap. The end of each board is cut at a 12 degree angle so it will align with the hub. Not every hub connection is exactly 12 degrees, but there is enough flex in the structure for the angles to average out properly.
Once the struts are cut to length, they are run through the table saw to add a slight bevel to them. When the dome is fully assembled, the polycarbonate panels will rest fairly flat along the bevel. This will also insure that the height of each strut is the same since it can vary slightly from the mill.
Next I remove some of the material from the end of each strut using a dado blade mounted in the radial-arm saw. This space will provide an area for the top tab of the hub to rest and provide enough clearance for the polycarbonate panels over the crown of the carriage bolt.
I built a jig to act as a stop and keep each strut aligned properly during drilling. This allows for a consistently placed hole to be drilled near the end of each strut. The placement of this hole is important so it will fit properly into the hub and provided an accurate length for the hub and strut combination.
And now, the perfect excuse to use one of my favorite tools!
The bottom of the head of a carriage bolt has a square neck so it can grab into wood to prevent it from turning. To get it to fit into the metal tab, I would either have to drill the tab’s hole larger, compromising some of its strength, or turn down the neck of the bolt in the metal lathe. I chose to turn each bolt and then will re-galvanize the area with cold-galvanizing paint.
Here is an example of how the final assembly will fit together. The strut is sandwiched between the two hub tabs and then tightened into place using a lock washer and nut.
This top view displays how each strut can pivot slightly on each hub. Since the angles of each triangle section aren’t the same from one section to the next, this allowed for me to make the same hub and allow the pivot against the bolt to make minor changes to the angles.
This side profile shows how the dado in the strut allows the polycarbonate glazing to clear the area without hitting the tab or bolt head.
Finally, this profile displays how the glazing will set flat into the beveled area that is cut along the top of each strut.
I assembled the base to verify that the calculations were correct and the pieces fit together. So far, so good!
That’s all for now. The next video I plan on detailing some of the site work. Thanks for watching!
Saturday, February 5, 2011
The first hub design had hanger bolts anchored into the end of each strut. The end of each bolt would go through a hole in a piece of schedule 40 3-1/2” steel pipe which was used at the hub. The strut was tightened to the hub with a washer and nut. This is the first prototype using the hanger bolt method and a PVC hub. The triangulation between each section was extremely strong. When I created a full scale prototype, the leverage of a full length strut and removal of the triangulated pieces cause the hanger bolts to easily pull out of the end of the struts.
The second hub design was similar to the hanger bolt design, except a hole was drilled through the strut and a washer and nut was inserted. This was to create enough surface area to prevent the bolt from pulling through the wood. However, testing a full scale prototype proved to be too much force against the strut and the bolt acted as a level and split the wood.
The third hub design is completely different. The strut is sandwiched between two spokes. Flat bar-stock is welded to the hub at the appropriate angles and a bolt is placed through the top spoke, through the strut and fastened with a nut under the bottom spoke. This full-scale prototype shows how 4 spokes of a 6 spoke hub would be assembled. A load test shows it can support my body weight on only 4 spokes, plus none of the other struts are used to strengthen the legs. There was some slight bending of the bolts from my bouncing but there was no hardware failure. Regardless, the final design will use 3/8th inch bolts instead of 5/16th.
The central hub is made from 3 ½” galvanized rigid conduit which is about ¼” thick. The conduit is cut into 3 ½” lengths. The galvanized zinc is ground off wherever the spokes are to be welded. Please note that working with galvanized material, especially using abrasion cutting equipment or welding should be done in a well-ventilated area. Also, you should always wear gloves and safety glasses.
I made up a jig that will safely hold the bar stock to the drill press. It allows me to consistently drill a pilot hole in the same location near the end of the stock. Since I have 480 holes to drill, creating jigs and templates is crucial for building an accurate hub. Once the pilot holes are drilled, I switch over to a stepped bit that will finish the hole at the proper size. I then flip the piece over and gently remove any tear-out from the bottom of the hole. Once the holes are in the end of the stock, I then cut it to the correct lengths. I built a stop for my abrasion saw so I could cut each piece to the same length. After cutting off the ends, I can go back to the drill press and drill a new set of holes for the next set of spokes.
Now it’s time to start assembling! This template has markings on it so I know where the locations are for the 5 spoke or 6 spoke hubs. I just place the hub over the template and draw a small mark on the hub.
This jig is used to accurately weld the spokes to the hub. The hub is placed over the post and each spoke is held in place with a pin. By using this jig, I can weld a complete hub in less than 15 minutes.
All the pieces are welded together with a standard MIG welder. Another safety note: Please weld in a well-ventilated area and free from items that can catch on fire. Also wear the appropriate gear to avoid burns from the hot metal and use a welding helmet to prevent blindness. Keep fire suppression equipment nearby at all times. No one else should be in the area while using a welder.
When each hub is complete, any dirt and rust is removed by sandblasting and is then painted with cold-galvanizing paint to prevent future rusting. I hope you enjoyed this video on making a hub for the geodesic dome. The next video will show how the struts are made. Thanks for watching!
Friday, February 4, 2011
Luckily, when I assembled the greenhouse, I had added some extra bracing inside. This prevented it from totally caving in so it’s not a total loss. The plants and fish are still alive! This spring, I should be able to dismantle this section and bend the pieces back into shape….and add some additional braces inside.
Here’s a link to my blog that displays the original bracing I installed a few years ago. Link to Blog
Monday, January 17, 2011
Wednesday, January 12, 2011
Sunday, January 2, 2011
One of the top requests I get is how to build a strawberry tower. This video will display all the necessary steps to build your own.
The first step is to place a mark on each end of the pipe, then rotate it 180 degrees and mark the other end. Then snap a line down the entire length of the pipe. You could also use a straight edge to mark a line, but I find the chalk line to be more accurate and easier. Turn the pipe over and snap a second line down the opposite side.
Along each chalk line you will place a series of marks. Starting at 2 inches, draw a mark every 8 inches. This will be the spacing between each pocket in the tower. If you are going to grow plants that need more root area, set the spaces further apart. I typically replace the strawberry plants every season. If they grow for more than one season, they can become root-bound.
Starting at the first set of marks, draw a line from one mark and connect it to the mark on the opposite side. Then turn the pipe 180 degrees and connect the next series of marks. Continue rotating the pipe while connecting each series of marks. These lines will be used for cutting the slots in the tower.
Along each cut mark, carefully cut through the pipe until you reach the measured mark you placed at the chalk line. Do not cut through more than half the pipe! Rotate the pipe 180 degrees and cut the next slot. When you are done, each slot should be on the opposite side of the previous slot.
Time for some good gloves. The pipe doesn’t become flexible until it is well above the boiling temperature of water. Please be careful!
The general area that will be heated will be an arch shape starting at one end of the slit, up about 8 inches to the back side of the neighboring slit and then back down to the other end of the slit.
Heating PVC should be done in a well vented area. If you overheat it, it can release some nasty gases. Please be careful! Continuously move the heat around the arched area. Try to avoid heating the area below the slit to keep the pipe from bending too much.
After a few minutes, the PVC will become soft. It helps to apply a little extra heat at the each edge of the slit since this is where the sharpest bend will be.
Push in the PVC so it makes a concave shape in the arched area. You will want to push it in enough so that it will touch against the back wall, but not create a seal since the water will need to trickle through that area, but don’t leave too big of a gap so your growing media will fall through it. When you let go of the pipe, it will usually spring back a little, leaving a gap around ¼”.
I found it to be very helpful to use a few spring-clamps to hold the tight bends in place while the plastic is cooling. You will want to hold the shape in place for a couple of minutes while it is cooling.
It takes me about 3 1/2 minutes to completly create each pocket.
When you are done, you will have some nice pockets alternating on each side of your new tower.
As the water flows through the tower, the surface tension in the water can cause it to flip out of the edge of the slit. To correct this, I added a collar around each pocket.
With some extra pipe, cut some rings about 1 ½” wide. Then remove enough of the ring so when it’s placed over the slit area, it extends just beyond the slit. Add some silicone adhesive and clamp the ring in place. Half of the ring should be placed above the slit line. Use clamps to hold it in place until it cures.
If you’re not going to be draining directly into a sump tank, you’ll need a way to catch the water from your towers. Take a 4” cap and add a fitting to it. Drill a 7/8” hole and thread it with a ¾” tap. There are several ways of adding fittings, but I found this to be very cost effective method.
Take a ¾” NPT to barbed fitting and screw it into the tap. If it is screwed in far enough, it will be higher than the base of the cap. This work well to help any media that as fallen through from going down the drain and clogging it.
This cross-section shows how the fitting is placed into the cap.
Place the cap on the bottom of the tower. The bottom pocket should not be filled with anything so you can clean the base cap if necessary.
To hang your tower, drill a couple of holes on both sides near the top and insert some S hooks. Use a wire or chain to hang it from a strong support.
To connect the tower drains together, you can attach them with tubing and barbed fittings. I made some stands from scrap 3” pipe to support the bottom of the tower. Then I used a 1-1/2” pipe with holes drilled in the side to catch the water from each tower. Each pipe then drained into the main sump tank.
Filling each pocket can be a challenge so I made a tray-type funnel to speed up the process. Take a section of pipe and do a cut down its length. Heat the entire piece so it can be flattened, then bend up the edges so it forms a V shape.
I created a cross-cut section so you could see the inside of the tower. Please note that this sample is done with black ABS so you could see the various surfaces easier. Each pocket will hold about 5 cups, or 1 liter of growing medium. This is enough space for most shallow root plants like strawberries or lettuce. For my strawberry plants, they will usually get water for 10 minutes every hour and a half.
Thank you for watching. Here’s a quick slideshow of my strawberry towers in action!