The Aerogarden is a counter top hydroponic garden. I've had this one for several years and have grown herbs, jalapeno peppers, cherry tomatoes and lettuce in it, but it has left me wanting a more DIY approach rather than the standard kits that they sell for seeds and nutrients.
The grow light bulbs use a proprietary pin socket which limits you to only the manufacturers bulbs. The bulbs are 26 watt fluorescent bulbs at a high color temperature so there is not too much that is special about them aside from the base. They are just standard 120V bulbs.
For nutrients I had experimented with some that I had purchased from a local hydroponic garden shop, they are a natural type and as a result tended to create deposits inside the Aerogarden which clogged it up and would seize the pump which killed some of my plants when it happened while I was away for a few days once. As a result I am upgrading the pump to a 158 gallon per hour pump I bought at Harbor Freight for $6.99 on sale. The pump runs on 120VAC whereas the stock pump runs on 12VAC so this will have to be accounted for.
For light bulbs I purchased a four pack of 26 watt (100 watt incandescent equivalent) 5000K CFL's from Home Depot for about $7. From what I've read 5000K seems to be the best overall color for this application, but some use 2700K color to encourage fruit production at later times in the grow cycle. I may experiment with different bulbs later on. The stock proprietary light bulb sockets will be replaced with standard type sockets and I am adding an additional bulb in the center to give this 50% more light output.
Here you see the finished product with much more light.
Step 1: Inside the Base
At this point I decided to take apart the base so take a look under the hood. The green PCB board is the main control board which handles the timing for the different selected light and pump cycles. The yellow PCB is the power distribution board which has relays for the lights and pump plus also has a 12VAC transformer for the stock pump.
There are two identical relays on the board, both rated 5A at 250VAC so there should be plenty of extra overhead for the extra bulb I am adding. I may also eventually switch the new 120VAC pump off of the same feed as the lights, this should handle it all nicely as everything will be less than 1A total (26 watt bulbs X 3 + the pump at 17 watts rated). There is a high output lighting kit made available as an option so I suspected that the unit was capable of handling more power either way.
I did not modify anything here as I wanted to make this somewhat reversible if I ever wanted to go back to stock. The transformer will continue to use some power so if I were more ambitious I may try to remove it.
Step 2: Remove Light Hood
Unplug the hood by wiggling the plug and pulling downward until it releases. Remove the hood from the base by raising it to the highest position and then press the retention button in once more and lift the hood straight up.
Step 3: Remove Bulbs
Carefully wiggle the bulbs loose from their sockets. I broke one in the process so be gentle.
Step 4: Remove Arm From Hood
Flip the hood over and remove the arm by bending this release tab back and pulling the arm out.
Step 5: Disassemble the Light Hood
Remove the nine Philips screws which hold the light hood together.
Step 6: Separate the Hood
The two halves of the hood will now separate easily. Note that the light sockets just slide in. Use some snips to cut the sockets out, but leave enough wire to work with as you will re-use the input connector to the hood.
For replacing the light sockets I purchased three ceramic standard socket bases, two steel light nipples and an assortment of hex nuts for these from the lighting aisle of Home Depot. The ceramic sockets were probably overkill for CFL's, but they were not much more expensive than the other bases they had.
To mount these to the hood I simply cut out a piece of scrap plastic to the same shape of the stock sockets using a cutting wheel on a dremel and put them in place. I intentionally made the fit tight.
Step 8: Drill Holes for the New Sockets and Install.
Drill holes in the plastic pieces made in the last step plus an extra hole in the middle.
The holes were drilled such that the sockets would be located away from the reflective surface of the hood. Standard CFL bulbs are wider than the stock bulbs used. A little dremel work was required on the back where the extra socket in the middle was added.
The threaded steel nipples were cut in to approximately 1/2" sections and threaded in to the sockets for mounting.
Step 9: Install the Sockets
Install the rest of the sockets and test fit the bulbs.
Trim the socket wires down, but leave enough slack to fit around the hood arm which will go through here. Solder and heat shrink the wires together.
Re-install the two pieces of the hood together. You will have to route the socket wiring around the hole where the hood arm goes. When re-installing the nine self tapping screws back the screw in to the existing thread to avoid cross threading.
Step 10: Upgrade the Water Pump.
This is a 158 gallon per minute submersible pump I purchased at Harbor Freight on sale for $6.99. It runs on 120VAC whereas the stock pump runs on 12VAC and it is considerably larger.
Start by removing the grow pod bay from the tub. Remove the filter from the pump, remove the screw which holds the pump electrical connector to the housing. Pinch two legs together slightly while lifting up on the black plastic piece on the bottom until it comes out. Push up on the pump to remove it from the base. There is one screw which holds the base on hidden by the pump, remove this screw and separate the two pieces of the base. The bottom piece will no longer be used.
Step 11: Install the New Pump.
This part I was not so thrilled with my solutions, but so far it is working. The stock pump fits neatly inside the housing that was removed to make room for the new pump. The water inlet to the distribution point is a short tapered inlet which seems to hold a hose pressed up against it by just friction, although not all that securely. By positioning the pump right under neath and cutting the extra piece of hose to fit I was able to get the weight of the hood to hold pressure on it when closed. The pump has suction cups so it helps to hold it in place during positioning and allows it to be slid.
A little dremel work was needed to cut a hole to allow the cord to pass through the back with the cover closed.
Step 12: The Result.
I'll call this a qualified success. The lights certainly are significantly brighter and the water flow is much increased. The hope is the increased water flow will keep the natural nutrients mixed up enough to prevent build up and the higher light output should result in better growth.
This whole project cost me about $40, which will more than pay for itself by the time I buy replacement bulbs, or perhaps may not need to. The stock bulbs are recommended to be changed every 6 months as they claim reduced light output. I do think I noticed this as the stock bulbs aged so I will keep an eye on it as these get older.
Step 13: A Follow Up Three Months Later.
It's been about three months and things are working well. I am using natural nutrients, which tend to cake up more than the synthetic nutrients. I was also previously using a root development supplement and it turns out this was not good for straight aeroponic so I quit using this and the buildup decreased significantly. Still, I have had to tear down the pump entirely once to clean it.
The initial start seemed to be slower than I recall, but now that the plants have had a good start they are really taking off. The stock Aerogarden with their nutrients would usually give me at the most half a dozen cherry tomatoes at a time. I currently have over 20 tomatoes which should ripen at nearly the same time. The results have been amazing.
My method for connecting the pump to the water distribution point has not been very good. When it is removed it takes several tries to get a good enough connection on it. I need to figure out a better solution to this at some point, but it will likely mean permanent modification, but at this point there is no reason to go back to the stock equipment.