You know asparagus ready to harvest when spears reach 6-8 inches (15-20 cm) tall with tight tips that have not started to open up yet at the top. The head should look like a closed bud not a tiny fern spreading out. Grab them at this stage for the best taste and texture on your plate.
I check my asparagus bed every morning during peak season in spring without fail. I sometimes check twice a day when the weather turns warm outside in my garden. Spears can grow 3-4 inches in a single day when temps hit the 70s°F (20s°C) outside. Miss a day and you might find ferns instead of food on your plants.
The asparagus harvest signs you want to see are firm spears with tightly closed tips at the top of each one in your bed. When the tip starts to spread apart into tiny branches the spear has passed its prime for eating. These opened spears turn stringy and tough when you cook them for dinner.
Think of asparagus spear maturity like a countdown clock that runs fast in your garden bed each spring harvest season. Each spear starts out perfect for eating but that window only lasts a day or two at most. After that the plant shifts gears and focuses on making fern growth instead of food for your table.
Penn State Extension gives a great rule for knowing when to stop cutting each spring in your bed. Watch the spear thickness as the weeks go by each season in your garden. When 75% of spears come up thinner than 3/8 inch (1 cm) in diameter the crown needs a break from harvest to recover.
To harvest, bend the spear near the base until it snaps at its natural weak point in the stem. You can also cut about 1 inch (2.5 cm) below the soil surface with a sharp knife if you prefer that method. Either way works fine as long as you get the spear while the tip stays tight at the top.
Store fresh spears upright in a jar of water in your fridge like cut flowers from the garden outside your home each spring. They stay crisp for about a week this way before going limp on you in the fridge. Or cook them the same day you pick for the sweetest flavor that store-bought spears cannot match at all.
Read the full article: How to Grow Asparagus from Crowns Successfully
