I've uploaded a new photo of the block diagram of the design I will be testing this month.|

I am currently modelling a 3D printable pot design that has an hollow interior with nozzles at the top and bottom of the pot to facilitate the flow of water around the soil itself to provide passive cooling from a connected water reservoir.

The general idea is that as the water moves around the soil, it transfers any residual heat or cold to the water maintaining the roots of the plants at room temperature.

Additionally, a second pump is connected to the plant pots to water them using a 3D printed multi-way valve.

I think this is actually a rather elegant solution. We'll also see which of the two moisture sensor designs works best long term. The single DS18B20 sensor will be used with the Homie framework to measure soil temperature.

Not pictured is a water resistant sensor I will be adding to the water reservoir to log temperature as a comparative datum point to the soil's. The objective is to prevent the lettuce from bolting or wilting under the sun in the 32 degree's experienced sitting on the window sill.