Question
i need to plant 20 trees at about 6 ft high as a privacy buffer,but there is no full sun but indirect sun ,should i do it
thanks

Answer
They will grow in Full Sun - Partial Sun.

Thuja Green Giant would be good planting for a fast screen effect. Spacing will not effect the height of the tree.

Thuja Green Giant is becoming more and more popular among landscapers, growers, and homeowners alike. This hardy, fast growing, conifer makes a perfect privacy screen in just a few short years.   

Green Giant will grow from 3 to 5 feet per year and will eventually grow to 50 feet or more with a fairly narrow spread. The color is a deep lustrous green and is pleasantly fragrant.

Green Giant  will grow in a wide range of soils in zones 5 to 8 and prefers a deep well drained fertile soil although it adapts well to frequently saturated clay soils. This is a tough tree and will not easily suffer damage from high wind or heavy ice and snow loads.  

Green Giant is drought tolerant after it is well established, exhibits no significant pest or disease problems, is deer and bagworm resistant and is hardy to -25F.

This new USDA US National Arboretum release as Green Giant has been evaluated since 1967 and will become the outstanding alternative screening-evergreen to the disease prone Leyland Cypress in the south and to the Hemlocks that are dying throughout New England.  Plant 5 to 6 feet apart for a really fast privacy screen, otherwise 10-12 feet apart. Green Giant can be trimmed to any height and width.