In Sonnet 15 the poet declares war on Time using grafting as his weapon
Sonnet 15 starts with a gardener's gloom: everything that grows is perfect for only a moment. The world is a theatre watched by the stars, and people swell and wither like plants. Then the final line flips despair into defiance, as the poet promises to graft his beloved back onto life with verse.
The poem is built as one long sentence of conditions. When I consider, when I perceive, then: the first eight lines stack up observations before the turn arrives. Growth is fleeting, the earth is a stage offering nothing but performances, and the stars quietly pass judgement on the show. Shakespeare, who made his living as an actor and sharer in the Lord Chamberlain's Men, reaches naturally for the language of the playhouse.
Human beings, the speaker notices, behave exactly like crops. The same sky that encourages them also holds them back. They boast in the sap of youth, begin to shrink once they reach their peak, and wear their fine condition down until nobody remembers it. The botanical metaphor is precise: people are not simply mortal, they are seasonal.
That thought makes the young addressee look all the richer, because youth is visibly on loan. In the third quatrain Time and Decay sit down together to debate how to turn a bright day into soiled night, a pair of personified villains conspiring against one face. The couplet answers them. The speaker is "all in war with Time for love of you", and the weapon is horticultural: "As he takes from you, I engraft you new." The garden imagery that opened the poem returns to close it, with verse cast as the new growth.
Notice that no children are mentioned. The speaker does not ask the addressee to do anything; he takes the burden on himself, offering his own lines as the route to survival. Shakespeare wrote most of his known work between 1589 and 1613, and his 154 sonnets sit beside plays that made the same wager, that words on a page might outlast the people in them.
Source: Sonnet 15: When I consider every thing that grows
