What are some really beneficial LOWER ab workouts that I can do at home?

Strictly speaking, there's no such thing as lower abs, there are just abs. Working only lower abs is like trying to stretch one end of an elastic band without the other.

If you are concerned about fat around the lower belly, that's a different matter, and is more about your diet than ab exercises.

Good exercises for abs are things like bicycle crunch (right eblow to left knee and vice versa), reverse crunch (lie on back with feet in air, then raise hips off ground), plank (press-up position on hand or elbows, hold for 30 seconds), the Hundred from Pilates. Or pike on a swiss ball.

Okay thanks! That was definitely helpful. My diet couldn't be more perfect so I've got that down... I just had a baby 8 weeks ago so that's why I was concerned w/the lower belly but since writing that question my abs have actually got better & more defined again like they used to be, I do the bicycle crunches but wanted to make sure I was doing the right thing & if there were other exercises I could do. I run also, so I'm sure that's helped. Anyway, thanks again.

Give yourself a break. You are not a supermodel with a personal trainer, cosmetic surgeon and chef. You're a mother with a young baby to look after and not enough hours in the day. Your body will go back to normal, but give it time.

You've been pregnant for nine months. It takes your body a few months to get back to non-pregnant status.

Kettlebell swings develop the abdominals fantastically. Powerwheels do so also, but kettlebells are easier, and in the cases I have personally observed, produce better results.