I have a privacy border along my house lined with Eastern White Pines. The
pines
have done quite well in the 4 years I have been in this new construction home.
The pines are now about has high as my house and I really don't want them
getting much taller, and I want to maintain the shape of the tress which are
full from top to bottom. BRBR

You can slow the growth of the trees, but eventually they will be 50 feet tall.
If you don't want a hedge like that, the correct solution is to remove the pine
trees now and plant something else.
That said, the temporary solution is to go over each tree every spring and
break the candles (new shoots) in half. You can remove the top candle
altogether, but this will change the shape of the tree. They probably don't
need any fertlizer at this point.
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)