Greenhouse Roof Failure!

A little mishap happened with our last snow storm.  The north facing roof buckled on the greenhouse from the snow.  From the photo, you can see that the 4 “rafter” pieces have all bent in.  The rigid foam insulation that I had installed on the inside has also pushed in.

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
 

Spring can’t come fast enough!

Building a Geodesic Dome Greenhouse - Part 1

Hi Everyone! We're Expanding! We are pleased to announce that we have just received the necessary permits to build a new greenhouse. This 1200 square foot, state-of-the-art building will utilize some of our latest technology to enhance the building’s energy conservation, as well as monitor and control an aquaponics growing system. The greenhouse will be used for our research and development, and it will become the focal point of the farm as a visitor center. Construction is scheduled to start this spring and we are eagerly waiting for the ground to thaw.

This video is the first part of a series I'll produce over the next year or so. I hope you enjoy the adventure! (click on the video image to view in a new window...blogspot likes to crop these grrrrr)

Below is the transcript....I put it in here for the search engines!

Hello everyone. I wanted to welcome you to my winter wonderland. A couple days ago, we received about 2’ of snow. Here it is, I’m standing in it at about knee height. Here’s a show of the greenhouse and the garden.

One of my exciting things that I’ve been working on is to build a new greenhouse. This area down in here, which is off of one of my main fields, is going to have a 900 square foot geodesic dome, along with an out-building attached to it for heating and storage. It’s pretty exciting that I’m going to be able to build this. It’s going the be a big improvement over my 120 square foot greenhouse. This wooded site here is where it’s going to be. All the old farm equipment and trees will be moved and the ground will get leveled off.

It’s going to take me about a year to build it. I’m going to do everything from scratch – no kits at all. This is the location again – it’s just off of one of my fields we use for growing corn.

At the end of my video, I’ll also show you some of the plans for the building and some of the ideas for how the aquaponics will work too. I also wanted to thank everyone for reaching a 1000 subscriber mile mark. It’s pretty good for the aquaponics folks. Not quite like some of the millions or so that some of the other guys get on YouTube, but it’s nice to see a good group of people following along with what we do in the aquaponics world. Thanks again.

This is the site plan that was needed to obtain the wetlands permit. It shows the existing land and outlines what type of grading and the types of erosion control that will be installed to protect the wetlands that are near the site.

This particular location was picked because it was near one of the fields and needed minimal amount of excavation work.

This is the side profile of the geodesic dome. It sits on a required 4’ frost wall and will have a shed on the north side that will house a wood furnace. This also shows roughly how the grow beds will be set up.

The foundation plan shows the 33’ dome, the shed area, and post footings for an open-air shed roof which will be used for wood storage.

This plan displays the grow bed locations and how they drain into a central sump tank. The sump will pump water to the larger fish tank. This tank will have a siphon that will drain through a swirl filter and into a second tank. The second tank will be used for extra water storage as a thermal mass. The water will then be pumped from this tank back into the grow beds.

Buried under the floor will be 4” perforated pipe. During the summer months, air will be blown through these to get cooler air from the ground. Over the winter, warm air during the day will be pumped underground into the thermal mass, which will radiate back up into the dome during the nights. Hopefully the wood furnace will only be needed on extremely cold,cloudy days.

That’s all for now. I hope you subscribe to this channel for future updates. I will be showing detailed plans on how the entire dome will be built. We’re hoping to get started this spring once the frost is gone. Oh, and this is our skating ring that we love to use during the winter!

Winter in New England

18" of snow...we'll get a few more before the storm is over. It's nice to see all that money I spend on heat goes right through the roof and melts it! (sigh)

How To Build Your Own Strawberry Tower

By popular demand, here's a video detailing how I build my strawberry towers. I hope you find it helpful! Full transcript is below. Click on the video image to watch in HD!

Hello everyone.

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!

Plastic Extruder - Continued

I was a bit surprised to received so many questions about my plastic extruder. Hopefully this info will answer some of these questions:

There are 3 sections: bearing chamber, hopper, and heating chamber. These are made with a section of ¾” black pipe (gas pipe) and ¾” wood auger bit fits nicely into the pipe. There is a little bit of gap between the auger and pipe. I was concerned the molten plastic would ooze back out of the chamber, but it was never a problem. This unit can consume virgin HDPE pellets or cut up milk bottles.

The bearing chamber is about 3.5” long and is mostly dead space. The shaft of the auger bit is long and I didn’t feel like turning it down shorter. At the end where the shaft comes out, there is a thrust bearing placed on it to minimize the friction.

The hopper has half of the black pipe cut away to expose the auger. This is 4.5” long and has a metal hopper which holds around 1 cup of pellets. As the auger turns, some pellets get forced into the heating chamber while some just sort of move to the front of the hopper. Between the hopper and heating chamber is ¼” of plywood…to act as a heat insulator to minimize the heat loss through the metal.

The heating chamber has two heating zones. The main reason was to attempt to heat the plastic evenly since I wasn’t sure how it would heat as it moved through the chamber. This chamber is 5 inches long. The first temperature sensor is placed about half way through and the auger bit ends just before it (so it won’t hit against the probe). The second reason was I didn’t want to run a high voltage through the Nickel Chromium wire…too dangerous and I had a couple of PC power supplies I could run 12 volts at 8 amps. The pipe is wrapped in Kapton tape which is heat resistant….but you can see in the photo it did eventually burn through. Each zone is independently controlled by a microprocessor to maintain a consistent temp.

The heating chamber has a flange on the end which allows different die plates to be bolted on to the end. Depending on the size of the “hole” in the die, the plastic will extrude at different speeds. For the 1/4” slot, the auger turns at about 18rpm and can produce a ribbon of material at roughly 200 feet/hour.

Plastic Extruder for Growing Media

For several months, I’ve been developing a plastic extrusion system that has been able to take virgin HDPE resin pellets, or shredded milk jugs, and properly melt and extrude them into a shape that could be used as a low cost growing media for my Aquaponics system.

There was a lot of trial and error to get to this point. The biggest problem is that the plastic retains little moisture. If the seeds aren’t directly placed in the flood/drain cycle, they won’t get any moisture to germinate. I typically grow in stone and some of the stone above the water line is able to wick and retain enough moisture to provide water to new seeds.

Another issue with HDPE is that it’s extremely smooth (again, works well to repel water). Even adding texture to the media during the cooling process, the media still is smooth, which makes it difficult for bacteria to stick to it. I was also a bit surprised to see that the roots didn’t really care to grow in it and they would grow around the edge of the net pot instead.

On the plus side, the plastic is light, fairly inexpensive, clean, and easy to work with.

I hope some of the info in the video is useful to some of my fellow aquaponic/hydroponic growers in their quest to find a better, more cost effective growing media.

EDIT:  There is now a second blog entry with some more details about this.... Click on the "Newer Posts" link near the bottom.

Below is the transcript for the video…no need to read it if you’re going to watch the video… I just included it so some of the search engines could pick up on the keywords. ;-)



Hello Everyone. Today I’m going to show a plastic extruder system that I built. The end result was to produce a synthetic, cost effect growing medium for my Aquaponics system.

The extruder consists of a hopper for high density polyethylene pellets. An auger then forces the pellets through a dual zone heating chamber. The heated material is forced through a small die at the end of the chamber.

The temperature in each zone of the heating chamber is controlled by a Teensy AVR microcontroller which is monitored and adjusted through its USB port connected to a laptop.

The auger is driven by a windshield wiper motor and it is geared-down using an old bicycle sprocket and chain.

The hopper is filled with HDPE pellets where they are slowly forced into the heating chamber. It can also be filled with shredded milk bottles or shredded milk bottle caps to add color.

The heating chamber is covered in some fiberglass insulation to conserve heat. There are two thermal probes mounted near the middle and end which provides accurate readings to the controller as the material is heated. The heating elements draw around 16 amps at 12 volts.

The molten plastic that is extruded from the die is squeezed through a set of rollers which embed a texture into the material. A small tube blows air onto the pressed material to cool it, and to keep the rollers cool.

This is one of the rollers after I turned it on my lathe with a close-up view of the texturing.

And this is a close-up video of the material being extruded and pressed through the rollers.

Here is a close-up view of the finished material once it has been cut to length. There is a waffle pattern embedded into the plastic which provides plenty of surface area for bacterial growth. The media lies flat which helps to retain moisture during a drain cycle. The pieces have plenty of spaces between each other for water and root growth.

Most HDPE plastic is classified as food-grade. However, one problem is that nothing likes to stick to it. Even though a texture has been embossed into the plastic, a small amount of movement can disrupt anything that was clinging on it.

This is a time-lapsed video taken with my PlantCam over a 30 day period. There are 3 bean plants growing. I also planted lettuce seed which didn’t germinate, probably because the top inch of the media doesn’t retain moisture like stone or expanded clay.

After 30 days, I removed the beans from the aquaponic system. I had the net basket wrapped in foil to prevent the roots from wandering into the surrounding stone. The roots seem to have an aversion to growing in the plastic and mainly grew between the basket and foil.

Thanks for watching. If you have any questions or comments, please leave them in the comments section below. Also please subscribe to my YouTube channel to see future videos!

Winter season - DONE

In a tragic turn of events, my winter season is over. The circuit breaker for the greenhouse tripped and it went through the night with no heat.

The outside temps went down to 21F (-6.1C) last night while the inside temps went to 27F (-2.8C). Everything got frosted except a few lettuce plants. Tank water is at 38F (3.3C)...goldfish are conserving energy by sitting at the bottom of the tank. They'll be perfectly fine this way until spring.