Computer controlled grow box – Part 1

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The Idea and Design

My PC Grow box was very effective though it did have some shortcomings along with my desire for tinkering caused me to create a new version code named “Project Everbearing” after the test subjects for the project, several Everbearing strawberry plants I propagated from my garden last Summer/Fall.  The specific shortcomings I wanted to overcome were temperature control and limited size.  My grow box has to live in my garage so on cold nights the temperatures can fall low enough to kill my summer seedlings (tomatoes/cucumbers)  Size is an easy fix just make it bigger though it is more difficult to keep a larger grow box warm and still well lit.�

My solution to both of these problems was the addition of a computer to the system.  First computers generate heat, using this along with computer controlled fans and incandescent lights (heater)  allow me to regulate the heat to my desired levels.  This is the point a normal person may have just stopped, but I am far from normal and decided a few more features, which I will explain more below.

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The Structure and Insulation

First comes the structure, upon inheriting a set of shelves from my sister, we ran out of room for some of our existing storage shelves (see above), though we used the buckets to store loose toys on our new shelves we had the structure of the old one sitting in the garage for some time.  After many passes by in the garage not knowing what do do with this shell, it finally came to me that this would be perfect for my new grow box, (Reduce/Reuse/Recycle) in action.  The only customization required was the removal of a couple of the wooden dowels and I was ready to add some hardware.  Of course you could do the same thing with an old bookshelf, cabinet or just with construct your own frame with a 12”X1”X8’ foot board cut in two along with two 1”X1”X8’ pieces of lumber cut into two.  Screw one 1”X1” in each corner and should should have a pretty solid frame.  For the top I used pegboard mainly because I bought a 4’ by 8’ sheet when I only needed half of it but worked really good to use zip-ties to secure various components and provides decent airflow between the computer and growing areas.

Second comes insulation, after some not so careful calculations and measurements I determined I could cover the 3 exposed areas with 2 sheets of 2’ by 4’ sheets of insulating Styrofoam.  I glued and taped (duct tape of course) the Styrofoam which was cut using a utility knife and straightedge to cut to size making sure I made the top straight and flush.  I then created an exactly copy of the other side and one more piece for the top.  Using a long strip of duct tape I created a hinge for the top and glued side of the box.  The last piece I simply fit into place using a tool box to ensure a tight fit but also allows easy access to plants when needed.

The Lighting

I went cheap on the lighting taking from the success of the PC grow box I decided to go with a similar setup using $2.00 home depot wired sockets hooked up to an couple old computer power cords.  I went with two 24 watt CFL bulbs and one incandescent bulb.  Though the incandescent is not as efficient and the CLFs it does provide a full spectrum of light and a little extra heat which the box can use in the many times cold garage where it lives.  The CFLs and incandescent exist on two separate circuits so they can be controlled independently by the software.

 

The Software — Grow box brains

Now I know all of this could be done with a Basic Stamp or Arduino pretty easy, but I wanted the ability to track history and have a decent user interface to look at, so I wrote a windows form application using C#.  To cover the basic functionality of temperature control I used the parallel port outputs hooked up to the computer’s parallel port to give the software the ability to turn the lights on and off.  By configuring a “sunset” and “sunrise” time which I am in complete control over the lights will turn on and off as appropriate.  I added some logic to ensure the plants stay at a comfortable temperature (thresholds configurable) by turning on the incandescent bulb when it is too cold and an exhaust fan when it gets too hot.  In order to allow the computer to know these temperatures I used a PS2 controller to create two temperature sensors one for the area the plants are growing and another for the top area where the CPU resides (computer was too old to have onboard temperature sensor)

ControllerSettings

My daughter thought it would be cool if we have some sort of automatic watering system.  I agreed, so I added a moisture sensor and created an algorithm to periodically check the moisture level and activate a water pump to add water until it reaches the specified moisture level.  I still need to buy and hookup the pump but coding portion is complete and tested.

I live in the Pacific Northwest it rains a lot and can get cold in the evenings and I don’t want to trek out to check on my plants.   solved this by adding the computer to my Wi-Fi network now I can take look at them by connecting to the machine wirelessly and see how they are doing through it’s webcam.  I also take periodic pictures of the plants so I can create cool time-lapse videos of progress like the one below.  I also have the ability to browse through pictures taken at specific time periods.

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Finally to store all of this data I installed SQL Server 2005 Express (free) which allows me to track historical data of the conditions and images over time.  If you have data, you definitely need some graphs.  Being too lazy to do this graphic work I leveraged ZedGraph (free) to allow some visual tracking of temperatures and moisture content.

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Features for future versions (Beta 2?)

  • Finish automated watering
  • Add automated red LED lights for flowering stage
  • Install LCD Panel
  • Make box look better (real door which does not require tape to open/close)
  • Create single USB controller for lights/sensors
  • Better/additional camera

Video of grow box “booting” up, personally I like the flashing lights when the computer sends signal through the parrallel port.  If you are old enough to ever have a printer that used a parallel port this is when it would make its annoying sound letting you know it was alive.

Updates:

Computerized Grow Box Update #1

Cheap grow box with LED Christmas lights

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I have one major problem last year with growing seedlings, running out of space.  I grow many different types of plants with various germination/growth rates and varied start dates.  This forces me to make sacrifices for placement of my movable light and eventually forced to move some plants outside earlier than I should.  The light needs to be close to the newly emerging seedlings, but can’t be burning the more mature plants growing into it.  My solution to this problem is a LED storage container grow box.  With this I will have a portable seeding area and since LEDs practically emit no heat the plants can literally touch the lights without problems.  At that time I move them to a larger grow box where it can continue to grow and start more seedlings.  I thought about creating my own LED matrix and buy individual LEDs and solder them together, but that sounded like a lot of tedious work and soldering, which I most likely would mess up.  Given it was after Christmas and LED lights were really cheap, this seemed like a good possible solution.

Materials cheap grow box with LED lights:

  1. 3 gallon Rubbermaid tub
  2. 1 string white or blue LED Christmas lights (50% off after Christmas)
  3. Drill with (1/4 in drill bit)
  4. Hot glue gun (may be optional)

Take a look at the number of lights on your string (mine had 60) then by measuring your tub figure out how you want to create your matrix.  Best to double check your measurements as you can see below I miscounted and only planned out 55 holes which I improvised and added 5 more after the fact.  You can also combine multiple strings if you want, given the low wattage you can string dozens of these together if you really wanted.

build cheap led grow box

Drill holes that will provide tight friction fit to the tub, for my lights this was 1/4 inch drill bit but for yours this may be more or less, I would recommend starting smaller and increase until you find just the right fit.  Once you have all your holes drilled fit each of the LEDs into the holes you drilled some of the connections between the bulbs will have a solid section in between (resistor) so depending on the spacing might be best to make this one diagonal of the previous light to make it not as tight a fit.  If you have some lights that just won’t stay in, apply a small dab of hot glue between the bulb and the lid.  This may diffuse the light a little  but very little intensity at the base so light loss should be minimal.

Last plug it in and check out your cheap LED light.  You may want to shake it upside a couple times and find any loose lights while your glue gun is still hot.

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Now some of your might be thinking (including myself) are these lights intense enough to allow adequate vegetative growth?  I did take a look at the LED matrix with my homemade spectrograph and it did show a high intensity of blue wavelength with minimal on red and orange/yellow/green so for this small space it may just work.  I am going to test it out on some guinea pig plants now and if I start seeing tall spindly growth I can easily switch out the current while LEDs with some ultra bright blue LEDs by simply pulling out the socket, swap out old LED (save some other project), replace with new LED, trim excess terminal wire, and push back into the socket.  Below is my proof of concept for this as long as the voltage/amperage is the same the circuit will continue to work, below is my proof of concept.

cheap led grow light

I also purchased a couple of red LED Christmas lights for plant flowering stage but have a couple months before I need to pull those out.

For build cost, this small storage container costs less then $2.00 and with the 50% off sale on Christmas lights at $3.00 I have a cheap grow box with full LED grow lighting for just $5.00 and about 15 minutes of assembly.

UPDATES:

Christmas light LED grow box – Update #1
Christmas light LED grow box – Update #2

Make your own paper seed packets (origami)

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When I posted about my adventures in saving onion seeds I mentioned the desire to purchase some small envelopes to hold the seeds. jimmycrackedcorn promptly responded with a comment scolding me for my lack of cheapness. Which I shamefully have to agree completely and took his advice and decided to make some of my own.

I followed the directions from the ICPS Seed Bank though I did do a little improvising to make the packets a little smaller and I got lazy on my folding so I have provided the cheap/lazy directions below.

Step #1: Start with a sheet of paper and fold down the middle, this will allow two seed packets per sheet of paper:

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Step #2: Use scissors to cut out the individual triangles which will be come your seed packets

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Step #3: Fold one corner one third of the way across the paper

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Step #4: Insert the other corner inside the fold and fold flat

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Step #5: Open top and pour in seeds, add a label, and fold over top

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I like this design since it is easy enough that even I can do it, it naturally has a funnel to pour in/out seeds, and is fairly compact which is good since my pickle jar seed holder in my refrigerator is getting pretty full.

How to collect and save onion seeds from your garden

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Last year I collected cilantro seeds and they were a great success in my garden that this past Spring I made a commitment to myself that I would try to collect more seeds this season.  Though I wanted to get more I was able to collect seeds from my onions, jalapenos, and cilantro.  The jalapeno seeds were pretty easy I set some seeds aside on a paper towel while making some salsa.  After they appeared to be dry I threw them in a brown paper lunch bag.

For the onions once the florets (flower balls you see above) got real ugly and dry and I could see the black seeds emerging I placed them in a paper bag before the birds got to them.  I then put the bag on top of our kitchen cabinets and forgot about them for couple months.  Today I pulled the bag down and confirmed they definitely were dry.  To separate the seeds from the pods I broke apart (which happens easily) and placed the contents into a metal strainer.  I gently broken open any remaining pods and agitate the strainer.  This causes the small black seeds to move to the bottom, allowing the pods to float to the top and forcing many of the stems to fall through.

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I then skimmed off as many of the stems/pods as possible leaving and putting the seeds into a brown paper bag until I can get into town to buy some more manageably sized brown envelopes (recovering from Seattle snowstorm)

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After a few minutes of work I now have hundreds of onions seeds which I probably only have use for couple dozen.  Seed exchange anyone?

Healthy Choice Cafe Steamers for seed starting/hydroponics

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Many times I see some packaging and eventually get an idea how I can reuse it with some minor modifications for starting seeds or some other purpose in the garden. I had one of these moment as soon as I opened my Healthy Choice General Tso’s Spicy Chicken Café Steamer   In case anyone is wondering what the purpose of this new packaging is, I could try to explain it but I will allow their marketing department do it for me:

“Our innovative product line utilizes a new and unique microwave Steam Cookerâ„¢–so you can lock in all the naturally fresh flavors of restaurant-inspired meals by steaming them yourself. With new Healthy Choice Café Steamers, vegetables stay bright and crisp, meat and seafood are juicy and tender, rice is moist and fluffy, and pasta is firm.”

After being delighted in the science of their frozen food steaming technology, I discovered I could easily repurpose the packaging completely as-is.

My first initial thought was to use this for starting seeds since it is the perfect size and depth for seeds starts before requiring their first transplant. As an added bonus they already have great drainage holes and even a reservoir in case of excess watering or allowing for wicking if I am going to be away from my seedlings a couple days.

My second thought was hydroponics, which is the process of growing vegetables without using soil. The basic idea is the plant gets all it needs from the nutrient solution which is applied always keeping the roots wet in the preferred growing medium. By adding a growing medium such as coconut fiber or Rockwool, adding some nutrient solution and an air bubbler to the bottom portion of this tray you have a cheap hydroponic system.  It is even big enough to support at least three small plants.

With either option the removal tray is also easily removable incase of overwatering or to change nutrient solution with very little disturbance to the plant(s).

One other benefit use is actually consuming the contents (preferable before used for gardening) which I did try and though the packaging has some interesting uses after you eat it, the meal tastes just about as bad as any other TV dinner I have eaten.

Effects of color spectrums on plant growth

I have written about the importance of lumens when growing indoors but the intensity of the light at specific wavelengths can be over even more important.  NASA has done some significant research on the subject to determine the possibility of growing leafy vegetables on a trip to Mars using as little electricity as possible to get the most benefit out of every watt.  In space any wasted energy (heat or light not used by plant growth needs to be severely limited.

It should not be a surprise that using LEDs is part of the solution they came up with since they use 20-30% of the energy of a comparable HPS (High Pressure Sodium) bulb which is considered very efficient given the lumen output per watt.  The most interesting part of their findings was how specific red and blue wavelengths were imperative to the growth of plants and actually could sustain growth with just these limited wavelengths.  Given the freezing temperatures and masses of snow on the ground the best use of this information for indoor gardening and specifically my $20 PC Grow Box.  Understanding the wavelengths that your artificial lights creates can help you have increased plant growth and save on your electricity bill at the same time.

When evaluating which light you must consider wavelength and also the intensity of the light at that wavelength.  A tool to do exactly this is a spectrograph, which you can purchase, make your own (this was a fun project with the kids), or just trust other peoples readings.  I chose made my own, but am displaying results (led museum) since I would have to estimate the intensity based on the brightness of the spectrum created which would lack some accuracy.

Just to get some perspective, this is what how various light sources appear to a spectrograph:

Sunlight spectrumSun
Florescent Bulb syl3500k
Incandescent bulb spectrumIncadecent
Low power  blue LED (5mm) spectrumBlueLED
Low power red LED (5mm) spectrumRedLED
Low power white LED SpectrumWhiteLED

As you can see incandescent appears to be the closest to matching the wavelengths and intensities of sunlight though it we need to remember that the orange/yellow/green wavelengths provide essentially are wasted from the plant’s perspective due to natural reflection of these colors.  So if a light looks bright to you, there is a good chance you are wasting electricity, as humans our eyes respond well to these wavelengths why we will find these bulbs to be much “brighter” from our perspective.  The fluorescent bulb is a good example where we see this light as bright for plants other than the small slices spectrum much of the light is unusable.  I have had good luck growing indoors with CFLs along with incandescent, but from the information above I my results cold have less spectacular if hadn’t included the incandescent bulb.  At the time the only reason I used it was to generate a little extra heat on some of the cold nights.

The key point is I could easily have much better results using significantly less power.  According to NASA’s research the most efficient configuration is to only have red/blue LEDs consisting primarily of red (80-85%) with the remaining (15-20%) being blue LEDs.  I would recommend replacing the some of the of the blue LEDs with white LEDs to provide a full spectrum including a pretty intensive blue spectrum in itself.  As an added bonus this will provide some “human” light in orange/yellow/green spectrum to allow us humans to view plants with less strain.

By replacing the two 24 watt CFL and one 80 watt incandescent bulb with a few hundred LEDs I could drop at least 124 watts with my new configuration.  Assuming I am running my grow box every day for 14 hours a day this could save me over $45 a year as well as just being the more environmentally conscious thing to do.

So during these cold winter months if you grow indoors whether just for seedlings or vegetables all year round be sure to remember that not all indoor lights are created equal.

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