Sattgrün

No — cards may be placed regardless of lighting or room color; lighting matches only grant verdancy when adjacent edges match, and room color only matters later for Room Bonus scoring (pp.7, 10).

You must place each card orthogonally adjacent to cards already in your home and keep everything within the 5×3 grid; cards may not be rotated or moved later (pp.6–7).

No — excess verdancy is lost: Fertilizer gives +3 to one plant but any surplus beyond the plant’s requirement is discarded, and the Hand Trowel gives +1 to up to three plants but cannot add more than +1 to the same plant (p.8).

No — when you complete a plant you remove its verdancy and place a Pot Token, and completed plants no longer receive verdancy from lighting matches or Nurture Item Token actions (p.8).

You may hold up to 5 Green Thumb Tokens between turns; spending 2 tokens lets you perform one of the Green Thumb actions (Token Reset, Card Reset, Ignore Selection Restriction, or +1 Verdancy) and spent tokens are returned to the supply (p.9).

Total the verdancy on all incomplete plants, divide by 2 and round down for points; ties are broken by the player with the most Green Thumb Tokens, and if still tied the tied players share the victory (p.10).