To slow down avocado ripening:

• Refrigerate unripe avocados
  • Place them in the fridge rather than at room temperature. The cold slows the enzymes and ethylene production that drive ripening.

* Keep them away from other ethylene-producing fruits (like bananas, apples, and other ripe fruits) to minimize cross-triggering ripening.

• Store cut avocados properly if already cut
  • If you’ve cut an avocado, wrap the exposed flesh tightly in cling film or brush with lemon/lime juice to slow browning, then refrigerate. The citrus acid helps slow oxidation, and an airtight wrap reduces exposure to air.

* For longer-term storage of prepared avocado mash, some suggestion is to freeze it (mashed with a bit of lemon juice per two avocados) and then freeze in airtight containers; this won’t slow ripening but preserves useable portions later.

• Practical notes
  • Whole avocados in the fridge can stay in a stasis state for a few extra days compared to room temperature, especially if they’re not fully mature yet.

* If you need to monitor progress, check ripeness by gentle pressure: unripe avocados yield slightly when pressed, but avoid pressing hard as they’ll bruise; once soft to medium yields under gentle pressure, they’re ripe or close to ripe. Moving between fridge and counter at intervals can help pace ripening for food planning.

Direct answer: To slow ripening, keep unripe avocados in the refrigerator away from other ethylene-producing fruits, and for cut or prepared portions, refrigerate tightly wrapped with citrus juice on the surface to slow oxidation and further aging. If you’ve already ripened and want to preserve freshness, refrigerating a sliced avocado (with protective wrap or juice) will extend its edible window by a day or two.