De or het groenbemesting?

The correct Dutch article is:

de groenbemesting

Rule Words ending in -ing: almost always de. See the rule

How to use groenbemesting

the groenbemestingde groenbemesting
this groenbemestingdeze groenbemesting
that groenbemestingdie groenbemesting
our groenbemestingonze groenbemesting
your groenbemestingjouw groenbemesting
every groenbemestingelke groenbemesting
which groenbemesting?welke groenbemesting?
a big groenbemesting / the big groenbemestingeen grote groenbemesting, de grote groenbemesting