Quite far. Not only do you need to synthesize the proper genomic sequence (barely possible), but it needs to be packed into a valid chromosome structure with a valid epigenome.

Then that needs to be placed into a cell with valid RNAs, compatible chloroplasts and mitochondria, compatible proteins in a compatible configuration, etc.

Creating all of that de novo for a plant is well beyond current capabilities.

This is why when we clone e.g. a sheep, we transfer a nucleus from the cell of one individual into the cell of a different individual. It is much easier to mix and match pieces of different cells from the same species, than to create those pieces from raw materials.

Creating artificial seeds, from scratch, based on a stored DNA sequence? Pretty far - that's still SciFi at this point.