When are My Sprouts Ready for Plant Food? (yCube Readiness Guide)

When you're sprouting yCubes in a Nursery (or tray with a vented lid), you need to know when your plants are ready to add to your Gardyn. What "ready for plant food" means depends on your sprouts' growth, and how much plant food is in your Gardyn.

Seedlings are sensitive. If nutrients are too strong, too soon, young sprouts can experience shock (wilting, yellowing, stalled root development) or even mortality. If nutrients are too weak for too long, growth lags and becomes stagnant. Matching the plant food dose to the sprout stage prevents stress, bolsters root development and speeds establishment.

1. You have your first dose of plant food (1/4 tsp per gallon) in the tank and want to add a few late sprouters.

2. You have a standard or mature dose of plant food (1/2 or 1 tsp per gallon) in your tank and want to add replacement yCubes from a Nursery or covered tray.

• If your tank has a first dose of plant food (1/4 tsp per gallon): add yCubes once you see any growth above the rockwool yCube surface.

• If your tank has a standard or double dose of plant food (1/2 tsp or 1 tsp per gallon): wait until at least one of the signs below is true:

  • True leaves present, or

  • Roots ≥ 0.5 in. out the bottom, or

  • Yellowing cotyledons (the first leaves) after a true leaf has emerged.

• Any growth above the rockwool.

• No need to assess other signs of plant food readiness if your tank has a first dose of plant food.

1. Confirm your tank has a sprout dose of plant food (1/4 tsp per gallon).

2. Inspect the yCubes in the nursery; move any with any growth above the rockwool.

True leaves are second set of leaves to grow after you yCube sprouts, and resemble the mature plants’ leaf shape.

• Tip: If you're unsure what your plant looks like when mature, check its page in the Plant Book!

Learn more about differentiating cotyledons from true leaves here.

Kale cotyledons (left) and later with true leaves (right)

Roots this length are mature enough to handle higher nutrient levels.

Half-inch roots growing out from the bottom of a Chives yCube.

The first leaves run out of nutrients as germination comes to a close, which can lead to yellowing or withering.

Yellowing cotyledons after a true leaf has grown.

Any plant that shows just 1 of these 3 signs can be added to a Gardyn with a standard or double dose of plant food in it.

1. Confirm your tank has a standard or double dose of plant food (1/2 teaspoon or 1 tsp per gallon).

2. Inspect each yCube for any one of the 3 signs of plant food readiness, outlined above.

3. Move each yCube that passes inspection from the Nursery to your Gardyn. Keep any that don’t in the Nursery for a few more days.

Remember, with our germination guarantee, we will replace any yCubes that fail to sprout after 21 days. See our replacement policy here.

Questions? Reach us at support@mygardyn.com, or chat with us! We're here to help.