Answer:
A house full, a yard full, a chimney full, no one can get a spoonful.
A time when they're green. A time when they're brown. But both of these times, cause me to frown. But just in between, for a very short while. They're perfect and yellow. And cause me to smile.
Gets rid of bad ones, short and tall. Tightens when used, one size fits all.
Upon me you can tread, though softly under cover. And I will take you places, that you have yet to discover. I'm high, and I'm low, though flat in the middle. And though a joy to the children, adults think of me little.
Many have heard it, but nobody has ever seen it. It will not speak until spoken to. What is it?
People take me on walks and I run and have fun. What am I?