Is the wood still wet? If its cedar, redwood, and esp Pressure treated, this is not necessary, you are doing it for only your benefit, the wood will take care of its self.
But, I never recommend using any stain, sealant, or topical chemical until the wood has completely, underlined, dried out. The drying out of green or wet wood will take the sealant with it.
If its new, wait until August depending on your region's intensity of summer heat.
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