Season Extension - Caterpillar High Tunnel

We previously looked at the construction of the caterpillar hoops for our soil beds.  In order to complete the caterpillar tunnel, we need to cover it with plastic.  The end product should look like this:

Our previously completed rib structure looks like this:

You can see from this photo that our soil bed is already filled with our growth medium mix, Mel's mix.  We have also filled in the cinder block holes with the soil mix as we'll be using these little spaces to grow the companion herbs, spices and flowers that attract good bugs and repel bad bugs.

You can see that the little cinder block holes are perfect for this.

We have our 55 gallon plastic water barrels in place to produce passive solar heating for the soil bed.  During the day, rays from the sun heat the water in the barrels.  At night, the water cools and as it cools, it radiates the built up heat back into the enclosed soil bed and heats the air.  This provides frost protection and allows us to extend the growing season.

Our first step is to ensure that the hoops are about the same height.  They don't have to be perfect, but it should be about the same height to prevent a camel tunnel.

Our next step is to get our plastic out.  You could use any construction plastic, provided it's clear.  You could also use specialized green house plastic, but that's expensive so we opted to go with construction plastic.  In theory you could use plastic thinner then 4 mil, but I wouldn't recommend it as it wouldn't provide much protection against radiation at night.  We decided to go with 6 mil plastic because it is heavy duty and should last a long time.  Remember you'll be installing the plastic and removing it again, twice per season so we want it to last.  I got the 20' x 100' roll as 20' was going to be wide enough to cover my hoops.  I had previously calculated we'll need about 26' wide, but slight tweaks to the hoops and spacing closer to the bed and the barrels allowed the 20' wide roll to work perfectly.

As you can see, 6 mil plastic is thick... very thick.  It allows only 60% light through and appears white, but it'll work.

Begin by rolling the plastic out next to the soil bed.  Be sure to keep it folded up as it comes off the roll.  This allows us to work with the plastic more easily.

IMPORTANT!!!  Remember to roll off more than enough plastic along the length of the bed.  The plastic is going to cover the bed and then slope down to the ground so some extra is needed.  It's better to have too much than too little.

Now pull the plastic over the hoop so as to position it in the center of the hoops.  Keep it folded as it came off the roll.  From this position, it allows us to straighten and tighten the plastic to the EMT ribs.

When properly positioned, there'll be a little sag between the ribs, but that's OK.

Now we need to secure our plastic to the EMT hoops.  There's many ways to do this, I'm sure, but the easiest and most efficient way to do it, is to buy these 1/2" EMT plastic clips from Johnny's.

They are well designed with an edge that tapers away from the plastic to minimize piercing of the plastic around the fasteners.  Additionally, they have a ribbed inside surface which prevents the plastic from slipping or pulling loose.  Though not cheap, these little babies are a major time saver so I recommend getting these.

Now go ahead and clip the plastic to the EMT ribs just to the side of the joint between the two pipes.

Once you have the center clipped, begin unrolling one side of the plastic down the ribs.

Attach a second set of clips half way between the first and the ground.

Repeat for all ribs and then unroll the plastic all the way to the ground.

Finally, another set of clips attach just about the ground level.

There should be some excess plastic at the ground level.  This can be cut away later.

Now repeat the process for the other side of the hoop.  Once the plastic is attached to the hoops, pull the openings on either end together in a V shape and stake it into the ground.

Here's the completed result:

It is important to note that practicality plays a larger role than theory.  This is a good example of that.  The reason I designed the tapered V was to break the wind and allow stronger resistance for the tunnel in high wind conditions.  In practice however, 6 mil plastic is thick and cumbersome to work with so pulling the tapered V together was not easy.  Additionally, when it rains, water collects in the tapered V creating a mess.  Access to the tunnel is also not as easy and the stake just doesn't quite seem to hold up so well when you are entering and leaving the tunnel on a daily basis.

This is where you'd have to weigh the risk of your tunnel getting blown away against the ease of use of the tunnel.  Creating a flat edge is easier to work with but risk high wind issues.  The choice is ultimately yours...

Soil Bed Preparation - Bottom

This post is way overdue, but with the flurry of spring activity, I haven't had time to sit down and write it.  Nonetheless, I found time so here we go...
We had completed the construction of our raised beds previously.  The design has two layers of cinder block for a total height of 16".  We constructed the cinder block beds right over the top of what used to be grass lawn.  There are two problems we want to address with the beds, before we fill them with our soil mix.

1.  Digging vermin like moles.
2.  The pre-existing grass and weeds.

Before we get into the way we chose to address these, allow me to share a quick tip.  See this photo:

The cinder block was set with the second layer overlapping the first and mortared into place.  We then used Quickcrete to pour concrete into the two corner adjacent holes to hold the corners in place and add strength to the beds.  Given that the foundation of the beds is just soil, some shifting is to be expected, but the walls of the bed doesn't have to do anything except contain the soil, so we believe this will work just fine.  Now let's deal with the moles.

In order to prevent moles from tunneling up from below the soil bed and wreck havoc in our garden, we are going to lay out chicken wire on the base of the bed.  In my scurry to get everything done in a compressed time frame after the freaking snow from the Winter from Hell finally melted, I built the beds before laying out the chicken wire.  The better way would have been to get 5' wide chicken wire and lay it out where the bed walls would be and then construct the walls over the top of the wire so as to hold the wire in place properly.  Failing to do that, we went with 4' wide chicken wire instead that fits snugly inside our 12' x 4' beds.  The soil mix will be heavy enough to keep the wire in place, but we do have a weakness on the edges though.  That, unfortunately, is a risk we're going to have to take.
Now let's look at the installation.  We begin with our roll of chicken wire.

The easiest way is to place the chicken wire roll on one of the 12' side walls of the bed and then simply roll it out to the end of the wall.

Be careful not to roll off the edge as it could pull the chicken wire crooked and mess with your alignment.

As you roll this out, you will either need another person to hold down the starting point of the wire or you'll need to anchor it somehow.  As I was working by myself on this, I staked down the wire in the starting corner with a piece of off cut EMT.

Now get your trusty tin snips and cut the wire.  Be careful not to cut too short.  You'd rather have some overlap which you can fold over than have the wire end up being too short.

Once done, the wire should be resting over the side wall like this.

Now simply remove the anchor and flip the chicken wire over into the bed.  Stomp it down into the ground and fold over any overlap you may have.

That takes care of the moles.  Now we need to take care of the existing grass and weeds that are at the bottom of the raised bed.  In order to do that, we're going to cover the bottom with weed cloth.  The reason for using weed cloth is to allow water to still drain out the bottom of the bed.  We do not want to inhibit drainage in any way.  Proper drainage is after all one of the main reasons we built a raised bed and filled it with our special soil mix in the first place.  The layout of our planting plan and the design of our row caterpillars resulted in our soil beds having just slightly more than 4' between them.  This allows us to roll out the 4' wide weed cloth perfectly between the beds.  Start by placing the weed cloth roll on one 4' end of the target soil bed and unrolling it to the other 4' end.

Now use your trusty box cutter to cut the weed cloth.  Be careful as they're sharp!!!  ALWAYS CUT AWAY FROM YOUR BODY AND FINGERS!!!

Lastly, simply flop the weed cloth over into the raised bed bottom and fold over any overlap.

Congratulations!  Your raised bed is now ready to be filled with our special soil mix.

Join us again tomorrow when we'll look at the construction of the half hoops for the caterpillar tunnels we'll be using for season extension.

Soil components

As we mentioned in the Keys to Success, the second key component is Mel's Mix.  Here's our core components for the mix as it was delivered to the house.  A rather large amount of work awaited getting the three mixed and into the raised beds.  The compost alone was 4 cubic yards.  For our mathematical calculations, I calculated the Peat Moss to expand to double it's size, but that's not really the case.  I had to get more Peat before we were done and by my estimate, Peat only expands to about 1 1/2 times it's compressed size.  Nonetheless, the mix got done!

Planting Plan - 2014 Season Summary

When we summarize our planting plans for two beds of corn, two beds of tomatoes, a bed of broccoli, a bed of lettuce and a bed of potatoes, we find that the following seeds are required:

Beans - 48 X 4 X 2 = 384 @ 250 seeds/pack = 2 packs X $10.29 = $20.58
Broccoli - 48 X 3 X 2 = 288 @ 100 seeds/pack = 3 packs X $3.95 = $11.85
Carrots - (96 X 12 X 2 = 2304) + (96 X 4 X 3 = 1152) + (48 X 10 X 3 = 1440) = 4896 @ 5000 seeds/pack = 1 pack X $10.50 = $10.50
Celery - 48 X 3 X 2 = 288 @ 250 seeds/pack = 2 packs X $3.95 = $7.90
Corn - 96 X 4 X 2 = 768 @ 1000 seeds/pack = 1 pack X $13.00 = $13.00
Lettuce - 24 X 6 X 3 = 432 @ 250 seeds/pack = 2 packs X $4.95 = $9.90
Lettuce (Butterball) - 24 X 6 X 3 = 432 @ 250 seeds/pack = 2 packs X $4.95 = $9.90
Onion - 96 X 2 X 1 = 192 @ 1000 seeds/pack = 1 pack X $5.60 = $5.60
Potato - 48 X 1 X 1 X 0.5 lbs = 24 lbs @ 25 lbs/pack = 1 pack X $19.50 = $19.50
Soybeans - 48 X 4 X 2 = 384 @ 500 seeds/pack = 1 pack X $10.29 = $10.29
Spinach - 96 X 18 X 3 = 8640 @ 10000 seeds/pack = 1 pack X $11.80 = $11.80
Tomato - 96 X 1 X 1 = 96 @ 100 seeds/pack = 1 pack X $27.80 = $27.80

Adding smaller packet totals together and upsizing to a larger pack saves money so be sure to keep that in mind.  Sometimes, if you need 300 and they come in packs of 50, it's cheaper to just get a pack of 500 rather than 6 packs of 50.

Needless to say, seeds have been ordered and now we are just awaiting their arrival.  Next step is to get the vermiculite, peat moss and compost delivered so we can fill the beds upon their construction completion.

Raised Bed Building - Day 4

With the temperature finally above 30F again, we were able to make the mortar mix and get the second level of cinder block onto the beds.  The mortar mix needs to dry overnight and then we're doing some concrete pouring in the corners to strengthen the beds, wrap up the fence and we're ready for growth medium!

West view:

South-west view:

North-west view:

North-east view:

Raised Bed Building - Day 3

Day 3 and the temperatures were once again to low to work with mortar mix so the actual beds haven't made much progress.  The fence however, is coming along nicely.

West view:

South-west view:

North-west view:

North-east view:

Raised Bed Building - Day 2

On Day 1 we laid the base layer for the raised beds.  We also drilled the post holes for the fence and concreted the fence posts in.  On Day 2 we moved more cinder block to the beds to be ready for mortaring the second layer to the first, but the weather wasn't cooperating and it was too cold to work with mortar mix  so we had to end there.  

Here's the view from the west:

Here's the view from the south-west:

The north-west view:

And finally, the north-east view:

As soon a temperatures rise above 30F we'll be able to complete the bed construction.

Raised Bed Building - Day 1

The massive amount of snow that had been covering my back yard, finally melted so it was time to start putting the plans into motion.  As discussed in the Planting Plan, the construction of 7 beds started.  In the image below, taken from the west, you can see the beginning framework of the beds laid out as well as the metal posts for the inner fence to keep my dogs out of the garden.

The image below, taken from the south-west, helps show where the passive solar heating barrels are going to go.

The image blow is taken from the north-west angle.

The final image is taken from the north-east angle, right next to the shed.

Unfortunately, cold temperatures (sub 30F) is preventing the use of mortar mix to add the second layer for now.

Potato Companion Planting Plan

We previously completed our Corn Companion Planting Plan, our Tomato Companion Planting Plan, our Broccoli Companion Planting Plan and our Lettuce Companion Planting Plan.  That accounts for 6 of our 7 soil beds.  Now we need to complete our Planting Plan for our potatoes.  As always, we'll reference the Purdue University Agricultural Extension Service's Indiana Vegetable Planting Calendar for determining our dates.  Potatoes are supposed to be planted at 12" intervals.  This is perfect in our SFG layout as it gives us one plant per square.  Since we expect the potatoes to fill out the soil as they grow, we're going to take a different approach to intensive gardening with this soil bed.  The allies for potatoes are beans, cabbage, corn, eggplant and peas.  

We're going to employ a different take on the vertical growth approach with our potatoes.  Since we're already going to be employing "hilling", we're going to take that a step further.  Hilling is when soil keeps being added around the potato plant to bury it deeper.  It forces the plant to grow a long underground stem from which more tubers form.  It's been reported to produce some good yields this way.  Our variety comes with a recommendation to hill 4" upon reaching 8" of exposed plant and to continue to do this until the hill is 12" tall.  Besides the irrigation complexity that such an uneven soil bed can bring, I wondered why not raise the entire bed level?  We'll be pushing the hilling boundary to see how much yield we can squeeze out of our potatoes.  As such, we won't interplant anything with them, but we'll employ a few border herbs for protection.  More on that later.  There really isn't a planting plan other than one seed tuber per square foot and hilling up 24" as they grow.  Using this plan we should get the following yield from our garden:

Our chosen potato variety is a mid season which means 80 days to maturity, row planted at 12" intervals with 1/2 lbs seed tubers, should yield (at 6:1) about 300 lbs / 100' row.  Thus:

1 crops X 1 plants per square ft X 3 lbs/ft X 48 square feet = 144 lbs of potatoes.

Our seed tubers ship late March to early April.  Let's assume we get them in the ground by the end of April, at a 80 DTM, that would put our harvest somewhere around the end of July.  If we were to replant at that point, we could potentially have another harvest by the end of October.  Given that potatoes are considered to be very cold hardy and our October 18th first Fall frost date, it's possible we may be able to double the potato yield by growing that second crop.  Since we can't get seed potatoes in July, we'll need to re-use some of our first crop potatoes for the second crop seeding.

Seeds required for this bed:
Potato - 48 X 1 X 1 X 0.5 lbs = 24 lbs @ 25 lbs/pack = 1 packs X $19.50 = $19.50

Now we need to determine the planting dates for these.  The earliest we can plant our potatoes March 20th however, the planting range stretches to May 10th and we are at the mercy of the seed company because these don't ship till late March.  We'll just have to sow these as soon as we get them.  Unlike our other crops, we'll probably sow this one with the entire bed at once.

Raised beds' raw materials arrive

We had ordered the materials needed for the construction of the raised beds.  We had opted to construct the beds using concrete cinder block for longer durability.  These bad boys weigh about 38 lbs each so for the 7 beds we plan to build, we got just shy of 14,000 lbs of block.  Big job ahead!  

The entire delivery below.  Even though we were in sub zero temperatures, we were still able to take delivery.

The 6 mil clear plastic rolls that will be used to cover the caterpillar tunnel for season extension and the Quicrete that will be used to hold the cinder blocks in the beds together.

We also got fencing materials required to erect a fence around the beds since we have a Weimaraner and a Dachshund and will need to keep them out of the beds.

Besides the fencing, we got some 3/8" rebar which will serve as the anchors for the caterpillar tunnel's ribs as well as some 1/2" EMT conduit that will be bent to form the ribs.

Boy that's a lot of block on one pallet!

And we have 4 pallets!

Now the construction can start and the vision can take shape.