First trimester.
Weeks 1–13. From before conception to the end of the third month — the quietest, least visible, and often hardest stretch to hold on to.
Week 1A seed, heldno size yet
Week 2The seed in soilno size yet
Week 3First root, unseenno size yet
Week 4Baby's-breath floretno size yet
Week 5Lilac floret0.2 cm
Week 6Forget-me-not0.5 cm
Week 7Lily-of-the-valley bell1 cm
Week 8Violet1.6 cm
Week 9Chamomile bloom2.3 cm
Week 10Cherry blossom3.1 cm
Week 11Crocus4.1 cm
Week 12Daffodil5.4 cm
Week 13Tulip bloom6.7 cm