Babysitter plants are hardy plants such as Hemianthus glomeratus (pearlweed) below that are not intended for the final aquascape, but are temporarily introduced at the start for the first 1 to 3 weeks to help stabilise the new tank. They are discarded when the tank is ready for the real tenants to move in.
This technique that has been used a long time by experienced aquarists.
While largely invisible to the human eye, a new tank's environment is a hostile, volatile one. Imagine the earth in its infancy!
Babysitter plants help accelerate the stabilisation of this invisible micro-biome. They also act as canaries in the coal mine:
If they continue to melt or remain engulfed by algae, it signals that the tank is not ready.
When new shoots start to look healthy, it signals that the tank is ready for the intended residents to move in.
Some finer points:
When uprooting the babysitter plants, take extra care to avoid disturbing the substrate too much.
Always siphon away the stirred up detritus before planting the intended plants.
To significantly increase the chances of success, the next simple hack is to always plant them 2-3 weeks AFTER we have introduced more hardy plants to a new tank.
This sequencing is deliberate, as the tank's invisible microbial balance is far more stable at that stage.
In many ways this is a variation of the Babysitter Plant approach.
For aquarists who keep fish, it is similar to adding the most delicate species some time after the hardier ones have been introduced.
Hack #3: Dark Start
We recommend the "Dark Start" approach, which involves:
adding the substrate and hardscape
filling the tank with water
letting the system 'cycle' for 3-4 weeks (filter on, lights and CO2 off) before planting.
Why not a Dry Start, which involves growing plants in moist emersed conditions for a while first?
Aquatic plants undergo profound changes when transiting from emersed (grown above water) to submerged conditions.
Just focusing on the aspect of CO2: The concentration of CO2 in the air we breathe is around 400ppm. In water, even with CO2 injection, most tanks average 20ppm or less, somewhat akin to suddenly reducing a daily 2000-calorie diet to 100 calories per day.
This transition is both traumatic and unavoidable, and we find that the dark start provides a smoother transition:
the aquatic biome has had time to stabilise in submerged conditions
tissue culture plants adapt directly to submerged conditions
store-bought submerged plants do not need to expend energy to temporarily transit to their emersed form and then adapting back to submerged growth forms
as all store-bought emersed plants have to adapt to their submerged forms anyway- let's get it over with at one go.
To help establish the tank's microbial ecology, it helps to seed the environment with beneficial bacteria, especially those involved in the breakdown of nitrogenous waste from fish and plants.