| What type of plant are you talking about?
In general, planting in sand is fine. My tank has sand substrate and I have a ton of plants that have grown successfully. If a particular plant is a root-feeder, it needs nutrients at the roots regardless of what the roots are buried in... since sand is inert, that might mean supplementing with a good root tab every 2-3 months.
Also, sand can compact over time, which could potentially trap toxic gasses or prevent roots from growing. To prevent this, you'd either need to stir it periodically with a chopstick or something similar, or have it stirred by burrowing tank inhabitants (such as malaysian trumpet snails). |