Common mistakes when crocheting T-shirt yarn bags and how to avoid them

1) Wavy base (too many increases)

Sign: the base forms waves (like a ruffle) and doesn’t lie flat. This usually happens because you’re making more increases than necessary in each round.

How to avoid it

• Check the increase pattern (make sure they’re spaced evenly).
• If you’ve gone too far, undo 1 round and repeat with fewer increases.
• With trapillo, try to keep the base flat without “forcing” it with your hand.

2) Domed or ruffled base (too few increases)

Sign: the base curves upward or “ruffles” in on itself. This is the opposite effect: there aren’t enough increases, and the fabric is too “short” to expand.

How to avoid it

• Add increases spaced throughout the next round (not all in the same spot).
• Check that you’re not unintentionally crocheting too tightly.
• If it’s already very ruffled, undo 1–2 rounds and repeat with more increases.

3) Twisted sides or sides that don’t rise straight

Sign: as you work upward, the bag starts to “twist,” becomes uneven, or opens at the top. This usually happens because of a sudden change in tension, failing to mark the beginning of the round, or not clearly defining the transition from the base to the sides.

How to avoid it

• Use a stitch marker at the beginning of the round if you’re working in a spiral.
• Work a “transition round” (for example, working through only one strand) to raise the side more evenly.
• Check every 3–4 rounds that the diameter isn’t increasing (if it is, you’re accidentally adding too many increases).

4) Uneven tension (changes the size and finish)

Sign: Some areas are tighter and others looser; the bag isn’t even. This is very common with T-shirt yarn because the material can vary slightly and because the weight tires your hand.

How to avoid it

• Support the T-shirt yarn and the work so you don’t crochet “in midair.”
• If you notice fatigue, stop and resume later: it improves consistency.
• Adjust the tension manually or change the hook size if needed.

5) Choosing a stitch that is too open for a bag

Sign: The bag loses its shape, “gives,” opens up, and reveals what’s inside. Tall stitches and openwork can look beautiful, but they don’t always support the weight of T-shirt yarn well.

How to avoid it

• For structure, prioritize single crochet (or more compact variations).
• Reserve open stitches for decorative areas or small bags.
• If you want a more attractive stitch without sacrificing strength, combine compact textures (e.g., raised stitches or BLO).

6) Handles that stretch or pull on the bag

Sign: With use, the handle stretches, the bag deforms at the attachment points, or the joins open up. It’s the most frustrating mistake because the bag may be perfect… and fail there.

How to avoid it

• Reinforce the attachment: add more stitches, more passes, or an internal reinforcing piece.
• If the handle is crocheted, use a compact construction (and add internal reinforcement if needed).
• If the bag will carry weight, consider handles made from a more rigid material (or combined materials).

7) Loose seams or weak joins

Sign: Seams open up, gaps appear, or the shape loses its structure. With T-shirt yarn, seams are points of real tension.

How to avoid it

• Use a firm, even join (and don’t “catch” only the surface strands).
• Reinforce the corners and the points where handles or closures will be attached in particular.
• If the bag is large, consider adding a lining: it improves structure and durability.

8) Not reinforcing the base (when the bag needs it)

Sign: the base arches under the weight or the bag “sags” when set down. In everyday bags, a little reinforcement makes a big difference.

How to avoid it

• If you want structure, add a concealed rigid base or internal reinforcement.
• Choose compact stitches for the base.
• Make sure the base is completely flat before building up the sides.

9) Visible finishing and ends

Sign: knots, ends, or joins are visible on the outside. In t-shirt yarn, joins can “bulge” if they aren’t integrated properly.

How to avoid it

• Incorporate joins in less visible areas (inside or at the sides).
• Hide the ends well inside the fabric (several centimeters) so they don’t come loose.
• Avoid large knots in high-tension areas (handles and joins).

10) Not testing the bag “in use” before finishing

Sign: the bag looks perfect on a table… but changes shape when you carry it or put things inside. T-shirt yarn responds to weight, so it’s best to test it before closing it completely.

How to avoid it

• Before finishing, put something inside (without overloading it) and carry it for a minute.
• Pay special attention to: the bag opening, handle attachments, and base.
• If anything gives way, reinforce it before the final finishing.

Recommended base tutorials

Many problems start at the base: if it’s built properly, the bag will practically make itself. Here are step-by-step tutorials to help you choose your base and crochet it with increases distributed evenly:

Final checklist (before considering it finished)