I haven't seen much discussion about weeds.

      While I'm a chemist and not a biologist, I have enough potted plants to have gained a good deal of experience about the nuisance value of weeds.
      First I might mention that bromeliads are monocots, that is, monocotyledons, as are grasses and pines. My weeds all seem to be dicots. This means that when their seed germinates it has a little food stored in the seed but not much. So it gets right to work and puts out a root and it pushes up a stalk with two almost circular leaves, the cotyledons. It has enough food to form the root and the two leaves and that's it. Then the "permanent" mechanism sets in. The cotyledons have the necessary chlorophyll to supply the "permanent" leaves that form next. So if you get the little beast before these form there is not enough left in the seed to start over.

      So when you see those two little leaves, pull them out right now and hence, no weed!

      So, I love to walk around and give the plants a little pat on the head for encouragement because I'm trying to grow them, thousands of miles from their home turf! They need all the encouragement they can get. But I have in my hand a special tweezer. It is pointed, about seven inches long with a little spade on the blunt end. I believe they are for people who work with beads! But they are great for grabbing these little dicots!

      Another thing I do that helps is to top dress the pots with a layer of 3/8 inch lava rock. Small pea gravel would work as well. This deprives the seed of soil to grab onto which would make them difficult to remove. So when I grab the little leaves with my tweezers the whole plant comes out because the root has not had time to develop the dirt grabbing ability.

      Another thing about these cotyledons. Most of them look pretty much the same. It's the secondary leaves that take on the characteristic shape of the mature plant.

      Here is a picture of a weed I just plucked out of one of my plants. Notice the two bottom leaves and their typical shape. Then notice the secondary leaf which has a completely different shape and is probably oxalis. This whole plant is less than an inch, top to bottom!.

      And here are the tweezers I use. They are available from