Minimal sufficiency (con que)

"As long as" with con que

To express "as long as" or "it is enough that," use con que. It introduces the minimum condition needed for an outcome. Because it sets up a hypothetical condition, con que is always followed by the subjunctive.

Let's look at building a self-sufficient terrarium (un terrario autosuficiente). Notice how the verbs following con que use the present subjunctive:

As long as you close the container, the terrarium will be self-sufficient.
Con que cierres el recipiente, el terrario será autosuficiente.
As long as you put the gravel below the substrate, the plant will thrive.
Con que pongas la grava debajo del sustrato, la planta prosperará.

Minimum requirements for growth

Use this same structure for your plants' minimal requirements to thrive (prosperar).

As long as the light is indirect, the plants thrive.
Con que la luz sea indirecta, las plantas prosperan.

When setting up a closed ecosystem, the water cycle takes care of itself. Just spray (rociar) the moss (el musgo) so the water can condense (condensarse) inside.

As long as you spray the moss with water, it will be green.
Con que rocíes el musgo con agua, estará verde.
As long as the water condenses inside, the terrarium is self-sufficient.
Con que el agua se condense adentro, el terrario es autosuficiente.
As long as you spray a little water, it will condense on the glass.
Con que rocíes un poco de agua, se condensará en el vidrio.