Growing at 8000'

I obtained a seed from a good quality, early blooming strain (Halloween) and started in on my window sill back in late Feb.
I transplanted it over to a 4 gallon pot with a mixture of vermiculide and soil from our garden (50/50 mixture miracle grow/native sandy soil).
We have had a cold and dreary spring in the Colorado mountains, and so my plant has been getting limited sunlight. It is 11 nodes tall and has started budding very well. It is just beginning to stay above freezing at night and our days are getting longer...

My question is: Can I continue to let the plant respond to the natural light cycle, harvest the buds when ready, and continue to vegetate until fall? Or will I need to clone the plant once it's buds have matured and have been harvested?

Any help is appreciated.
Thanks.

Here is what I am looking thus far:

http://i177.photobucket.com/albums/w...s/May10037.jpg

I think it is looking good, just a little short from lack of light...can it come back for a second harvest?