Sun lamp

See also: Standing lamp

Sun lamps provide artificial light to roofed growing zones (greenhouses) at high power expense (2,900 watts). A sun lamp will illuminate tiles within a five-block radius at 100% and outside tiles at only 50% or less. Sun lamps automatically turn themselves on at 06:00, and then off again at 19:12 to save power while the plants are resting. This energy-use pattern means while they have a peak power draw of -2,900 W, they only consume -1595 W⋅Days, and that they can be efficiently powered by solar panels. Once installed, the lamp menu offers the option to create a growing zone that matches its radius (100 tiles in total, not including the tile occupied by the lamp itself). It is constructed with 40 Steel in 330 ticks (5.5 secs) after Electricity has been researched.

It heats at a rate of 3 heat per second^{[Exact mechanic unclear]}. Unlike many other heat sources, it does not appear to have a maximum temperature and will continue to heat up rooms indefinitely.^{[Confirmation needed]}.

Short circuits

Rain on a powered sun lamp will cause short circuits and fires. A roof will prevent this.*

(* When planning/building a greenhouse larger than the area covered by the sun lamp itself (e.g. for stockpiles, multiple sunlamps or other structures), remember that a roof will collapse if further than 6 tiles from a wall or column, which is only 1 tile further than the sunlamp's effective growing radius. The four unlit "corners" beyond the lit area (see image, below) are safe places to plan for this sort of expansion.)

If the area is unroofed, you can simply switch the sun lamp off to prevent shorts. In biomes with a growing season, turning off the sunlamp and removing the roof can help save power when the weather is warm.

Greenhouses

Sun lamps allow indoor growing but don't produce heat, so heaters may be required to attain proper conditions for plant growth. Solar flares will cut the power, so prepare a shelf with emergency wood to build campfires to keep the room temperature above -10C/14F (below which most plants will rapidly die). Double-width walls provide more insulation against temperature changes (and thus save power on heaters or coolers), as well as offering better protection from attacks.

Sun lamps placed on dirt can let your colony produce things like corn or smokeleaf even during a toxic fallout, or in a cold biome with no growing season. If you maintain proper growing temperature, a dirt floor greenhouse will have 100% fertility on normal soil and 140% on fertile soil. As they cannot be grown under roofs, trees such as pine, birch, saguaro or cocoa trees may not be grown in completely closed greenhouses. They may only be grown in greenhouses with roofs open in a grid pattern, that leak a lot of temperature-controlled air.

Hydroponics basins boost plant growth to 280% speed and do not require soil. However, they can only grow certain crops and are dependent on electricity. If a hydroponics basin loses power, all plants on it will die quickly. The configuration in the image below will fit 24 hydroponics basins under a single sunlamp, for a total of 96 hydroponic growing spaces and 4 grow lit tiles.

If you have biofuel refineries available, you can use food produced by hydroponics to fuel chemfuel generators to help power the greenhouse array. This is so efficient that it violates thermodynamics, and leaves you with spare food for your colonists as well.

In 1.0 you need to place the sun lamp's growing zone manually. It can be made as a plus sign (+) in which each line is 5 tiles wide by 11 tiles long, with a 9 by 9 square in the middle. You can use the Planning tool to map this zone before placing your sun lamp.

The lamp blueprint will show the outline of its light radius until it is placed. Once the blueprint has been placed, the light radius won't be visible again until the lamp has been built.