The Cheap Vegetable Gardener

Soil Logic Moisture X-Tend testing and review

Aug 16, 2010 Uncategorized, moisture sensor, product review, water

I was contacted by SoilLogic and offered a free sample of their product Moisture X-Tend.  Though I could attempt to describe their product, I will let them do it in their own words…

Moisture X- Tend helps water penetrate the surface of the potted soil easier and remain within the soil root zone up to 4X’s longer than untreated water.

This innovative soil moisture management product helps prevent water from evaporating too quickly or draining past the roots of the plant. Moisture X-Tend is so easy to use – just add and mix the recommended amount directly to our watering can and water as usual.

The specific claim on the bottle that got my attention was that by using the product you can actually water plants 4 times less often.  I must say I was a little skeptical about this claim, though I decided to give it a try. 

My first attempt was shortly after I brought out a couple of my pepper plants from my grow box.  They both were bearing fruit of similar size and overall plants were of very similar size.  I started by watering one plant with water and the second with Moisture X-Tend and I observed their physical appearance over a period of time.  There was one problem on day two it rained ruining my results.

Having an empty client controlled grow box in my garage equipped with a moisture Vegetronix sensor, I decided this would be a great place to conduct my testing.  I watered two identical pots filled with Miracle Grow Potting Mix (without moisture control) with 250ml of liquid.  One being purified water, the second with Moisture X-Tend as described in the directions and monitored the moisture saturation over time.

As you can see the Moisture X-Tend started out with a much greater water saturation immediately after the watering and continued to hold the moisture 1.5 times longer than water alone.

Now this 1.5 times is quite a difference between the 4 times claim on the bottle, though in their defense this was from a single application and the FAQ on their website mentions that watering frequency is reduced after about a month of use.  I also was using a 4 inch pot and I would suspect that a larger pot would show better results.  If there is interest I am considering extending this experiment over a longer period of time to attempt to prove/disprove the 4 times claim that they mention on the bottle.

Though for me this is not practical to use all summer Moisture X-Tend is a great option when you are going away for a few days on vacation and do not have an automated watering solution or are forgetful like me and just get busy and neglect those poor plants for a day (or two) too long.

Tags: water

1 Gallon Milk carton upside down tomato planter

May 15, 2010 cheap, peppers, tomato, upside down planter, water

I wanted to see if (how much) my yields varied by allowing more volume of dirt in my homemade tomato planter, so I made this variation with the same type and size “Husky Cherry” seedling I am using in my 2-liter planter version.

The build for this one is also very simple:

• I started with an organic milk carton given it was already opaque, but if you have the non-organic variety you will want to paint or cover the outside with duct tape.
• Next cut or drill a 1/2 inch hole on the bottom of the milk carton, this will be where the stem of the plant will fit through.
• Cut four slits out from the center of the 1/2 inch hole to make it easier to insert the plant into the planter.
• Insert plant through the bottom.
• Fill with soil (mix of 1 part peat moss/coconut coir)
• Finally drill a hole and feed though eyelet secured with a nut from the back side

Now here is where you can stop or you can go with the advanced auto-watering option.�

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Tags: cheap, garden seeds, organic vegetables, outdoor plants, tomato plants, upside down tomato planter, vegetables

Solar Powered automated Rain Barrel watering system

Mar 29, 2010 electronics, water

This is a very cool project, grab a few rain barrels, timer, water pump, and a solar panel and have automated the tedious task of watering.  With all the rain we get (especially this week) in WA could fill up a dozen barrels in a short time.  My only suggestion would be to add a moisture sensor to only water when it has not rained lately.

Might be another project to add to my ever growing list…

Tags: cheap, vegetables

pH needs of plants in soil or hydroponics

Jan 6, 2010 hydroponics, pH, water

With the exception of some of my acid loving plants and flowers I normally do not have to worry much about the pH of my soil.  This is because I have amended my gardens with nutrient rich soils in raised beds over my alkaline clay I get naturally in my area.  This and the fact that due to natural and manmade causes the rainfall is slightly acidic and given the average range for the sweet spot of most edible vegetables (see table below) is 5.8 to 6.0 having your soil slightly acidic this is perfect.

Now when it comes to hydroponics this is entirely different.  My tap water has a pH of around 7.5 and the fluctuation of plant using nutrients and transpiration can cause great havoc on the pH on your hydroponic system.  Now this creates a challenge but also an opportunity to have control with great precision your pH and keep your plants growing in the sweet spot for the healthiest plants and the greatest yields.

So whether you are growing hydroponically, or simply trying to figure out why your Fennel didn’t do so well last year take a look at the table below, hopefully for some hints of what happened.

Recommended pH Ranges of Vegetables/Herbs

Tags: garlic bulbs, herb garden, outdoor plants, pepper plants, peppermint plant, tomato plants, vegetables

How to make a cheap soil moisture sensor – Heavy Duty Version

Nov 8, 2009 cheap, electronics, moisture sensor, water

My original version of my moisture sensor has worked great for me but it did have a couple flaws.  The first issue was construction, though I had great luck on my first attempt though after trying to recreate additional sensors given the small amount of gypsum between the sensor and the probes were so thin it was extremely easy to crack the sensor and I normally have about a 25% success rate on later creations (must have had beginners luck on the first one.

The second issue was durability.  Given we are playing with gypsum and as it is suspended in water it will eventually breakdown and there is very little we can do about it.  Though with my latest changes to my automated grow box which includes automated watering based on moisture content I want to ensure my measurements stay accurate throughout the season.  To help with this I have decided to increase the sensors size and also am using galvanized nails to prevent rusting.  After a few attempts I have come up what I feel is a pretty foolproof method of creating a moisture sensor.

How it works:

There were many questions in the comments in the previous post so hopefully I can clear this up a little here.

Technically a gypsum block measures soil water tension.  When the gypsum block is dry it is not possible for electricity to pass between the probes, essentially making the probe an insulator with infinite resistance. 

As water is added to the problem more electrons can pass between the probes effectively reducing the amount of resistance between the problem to the point when it is fully saturated where the probe has virtually zero resistance.  By using this range of values you can determine the amount of water than exists in your soil.

Parts:

• Plaster of Paris
• 2 Galvanized Finish Nails
• 1/2 inch plastic tubing
• utility knife

Construction:

Take your utility knife and cut the tubing slightly longer than your galvanized finishing nails.  Try to make the cut as straight as possible though it doesn’t have to be completely perfect.

Use your utility knife to cut the smaller plastic tube lengthwise, this will allow easier removal of your soil sensor after the mold cures.

Optional: Make the cut diagonally to prevent a potential vertical fracture line.

If you were very careful on you vertical cuts you can avoid this step, but to completely avoid spilling plaster onto my workbench I drilled four holes slightly larger than your tubing.  I used these holes for support but also to catch any of the plaster in the gaps from you less than accurate vertical cuts.

Being careful that the tubing fits together where you split the tubing vertically, insert the tubes into the holes (or carefully on a flat surface)  Mix Plaster of Paris and carefully fill with to the top.  The friction between the tubing should keep a water tight seal where you made the cut, though if the plaster is a little thin and it appears to be leaking through wait a couple minute for the plaster to setup some and try again, at that time it should not have the viscosity to seep through the very small gap that may be causing the leak.

Take your two galvanized nails and push them through a small piece of wax paper.  You may also allow the plaster to setup for a few minutes and then float the nails in the the plaster.  I like the first method since gravity will help ensure they fall straight down and parallel to each other.  As for spacing, I have done some experimentation with the gaps between the probes and my conclusion was, it doesn’t make much difference.  As long as there is a gap (they are not touching) you should get reliable results.

After allowing the sensor to cure for about and hour remove it from the holes you drilled in the wood.

Gently pull back the plastic tubing and you have a nice clean soil sensor.

Lay them out to dry for 24 hours to cure completely and their construction is complete.

img title=”IMG_4590″ src=”http://lh3.ggpht.com/_Xcv0VbxbRcc/Svd1RbUmfqI/AAAAAAAABWo/GpYqC3woNuw/IMG_4590_thumb.jpg?imgmax=800″ border=”0″ alt=”IMG_4590″ width=”400″ height=”267″ />

For attaching the wires there are a couple options.  The best would be to solder them to the probes though to do this you need to heat up the nail hot enough to enable a strong solder connection.  My little 15W soldering iron just can’t produce the heat for this so I am option for the wire wrap method.  I take about an inch of wire and strip off about an inch of insulation and tightly wrap around the probe.  Given copper will rust and could be a point of failure you will want to insulate this connection and the probes from the moisture.  A few dabs of hot glue works pretty well.  I am planning on trying liquid plastic, though I am currently out and when I have some on hand I will update with how it went.

How to use it

You can simply hook up a multi-meter and check the resistance though if you want to create anything automated you would need to use an integrated circuit (IC) or a electronics prototyping platform such as Arduino.  By applying voltage to one side of the sensor and using a voltage splitting circuit connected to ground and an analog input you can then measure the voltage making it through the probe.  The higher the voltage, the higher the moisture content of the soil.

Conclusion

The above should give you everything you need to know to create your own soil sensor and how to use it.  This can be used as a soil sensor for watering your indoor plants like I am using it.  This same sensor could be for monitoring your outside soil moisture content to trigger (or preempt your irrigation system) to save some money on your water bill and/or maintain consistent moisture levels in your plants which could drastically improve water sensitive crops such as tomatoes.

Tags: arduino, cheap, growbox, led, outdoor plants, tomato plants, vegetables

Computer controlled grow box – Part 2

Sep 29, 2009 indoor growbox, water

Though I have made some significant changes to the grow box controller, the actual grow box has undergone some minor but important changes over the past few months.

Automated watering

Now I must say this one is pretty darn simple.  Though I will be planning on a slightly more complicated hydroponic setup later I decided to start with a very easy bottom watering technique.  Just take a regular old fountain pump (I went with the cheapest I could find) drop it in a 5 gallon bucket of water and attach a hose long enough to reach your planting tray and plug in the power to the pump to your grow box controller and that’s about it.

To prevent evaporation and algae and little bugs making a home in my nice bucket of water, I added a lid with two holes for the water output and power input.  The power input required me to make a straight cut with a utility knife to ensure a snug fit while not requiring me to cur the AC line to feed the wire through.

I also cut a hole of the same size as the water output on the bucket lid to the grow box to allow the line to enter while still keeping the box closed.

Exhaust fan control

Air circulation is important for plants to be healthy but when the box gets warmer than expected I installed two controlled CPU fans to help regulate temperate as well as one static fan that constantly pushes air from the top to bottom.

I added a 12 volt exhaust fan to the top of the box (pictured above) to help push hot air out of the grow box with another (pictured below) at the lower part of the grow box to push in cold air as needed.  Both of these fans are powered by a 12 volt power wall adapter plugged into the grow box controller.

Heating

Though the computer and lights allow the box to create a comfortable internal temperature, sometimes it needs a little help.  For this I installed a regular old seedling heater to hopefully take a little sting out of the cold floor the seed tray is sitting one.  Like other components this was simply plugged into the grow box controller.

Putting it all together

My previous version was a little sloppily put together with duct/packing tape (lets just call it prototyping).  Though this added some hackiness appear it wasn’t too functional so I added a little strip of wood to support a couple hinges which I created a top which holds the LCD panel.

Upon opening the top you can see the grow box controller and the state of the art 600 MHz PC in all their glory.

As you can see I have still have some cleaning up to do with compress air and maybe a few more zip ties but all in all everything seems to have come together nicely.

Tags: cheap, garden seeds, grow lights, growbox, led, outdoor plants, vegetables