The Light-Top is the heart of a Space Bucket. It contains the main lighting configuration, and as such determines the performance of the indoor garden. If the light-top is underpowered, plants will grow long and thin which makes it unstable; if it is overpowered, heat and photosynthesis issues will be common (there is such thing as too much light for a plant). A light-top can be made with either CFL or LED lighting.
An array of CFL bulbs with glass shielding
Compact Fluorescent Lights are the cheapest option, but also the hardest to optimize. CFL bulbs emit a lot of heat that needs to be extracted from the plant chamber, and because of that, extra airflow is needed. The best CFL bulbs for Space Buckets are the 23 and 42 watt versions, which feature a good balance between heat and lumen output. Bulbs over 42w can be a safety hazard in an enclosed container, while bulbs under 23w are not an effective option.
LED lighting is the present and future of Space Buckets. This technology has a smaller heat footprint, something essential for indoor bucket gardening. These lights also have a higher lumen per watt output. There are two main LED options for bucket gardening: traditional bulbs (with E27 sockets), to UFO style fixtures.
A typical UFO LED light
The best option for LED Space Buckets are UFO LED grow lights, which come in a round shape that fits a bucket perfectly. With this option, it is just a matter of putting the light on top of the lid and plugging it into the wall. UFO LED grow light are the plug and play solution for Space Buckets.
These lights can be found in a variety of wattages. For the classic Space Bucket with 5gal containers, a 135w UFO LED light is enough. For supersized builds that feature 10gal containers, 180w are a better option. For Space Buckets that use stacked tote, a 300w UFO will be essential. As a general rule of thumb, the bigger the container, the more wattage will be needed for optimal results.
Some bucketeers install the UFO inside the container, which is not recommended and usually requires the reversal of the light fans. Though this is a viable option, it is better to install the UFO light outside of the container, which keeps the heat away from the growing chamber.
LED bulbs have become an interesting option for budget-minded bucketeers. The best bulbs for these kind of buckets are 8.5 to 10w. A LED-bulbed SB can be made following a SAG style build blueprint. In this case, 4 or 5 bulbs are installed vertically on the bucket lid. The plastic covers can be removed to optimize the bulbs lumen output, but for some newer models that is not recommended. For safety reasons, if the bulb has over 20 LEDs inside, it is better to keep the cover in place. One solution to the problems caused by the uncovered LED bulbs is to install a heat shield, which is fitted between the lights and the plant chamber. This is an essential upgrade for buckets that have high temperatures, and a great way to cover the exposed parts of the light fixture. The preferred material for heat shields is glass, which can be custom cut and stays cold to the touch. Acrylic or plexiglass can also be used, but is has to be monitored more closely (acrylic can melt or warp under high heat conditions).