During Phase 4, irrigation shifts toward a more vegetative steering impulse to support peak flower development. Smaller, more frequent irrigation events, higher daytime water content and reduced overnight dryback help maintain readily available water while reducing root-zone stress.

As the crop enters Phase 5, irrigation shifts back toward a generative steering strategy. Larger, less frequent irrigation events and increased dryback help create progressively drier root-zone conditions while maintaining root health as crop water demand begins to decline.

As flowers ripen, swelling and expansion slow and the crop progresses toward harvest. Pistils at primary bud sites may turn orange or brown and recede into the calyx, while trichomes may become cloudy or amber and some cultivars may develop darker coloration.

Maintaining appropriate root-zone moisture, climate and airflow becomes especially important as flowers become denser. Grodan's Phase 5 guidance emphasizes controlled drybacks and avoiding excess moisture, which can increase the risk of Botrytis and other microbial contamination.