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
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
Step 3: Remove Bulbs
Step 4: Remove Arm From Hood
Step 5: Disassemble the Light Hood
Step 6: Separate the Hood
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.
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
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.
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.
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.
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.
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.