What You Need Before You Start
A sew-in requires thread, a needle, weft hair (the sewn tracks that hold the extensions), and your natural hair braided into cornrows underneath. You will also need hair clippers or scissors, a rat-tail comb for parting, and either a wig cap or a stocking cap to wear under the finished sew-in. Some people use a mannequin head with a clamp to hold their work steady, though you can braid and sew on your own head if you are comfortable reaching the back.
The thread should be strong enough to hold weight—many stylists use thread made for sewing hair, which is thicker than regular sewing thread. Your needle needs to be small enough to pass through the weft without tearing it, but large enough to hold the thread securely. If you are new to sewing hair, a curved needle is easier to control than a straight one, especially at the back of the head where angles are tight.
Key Takeaways
- Cornrow your natural hair in straight, even rows from front to back, leaving space between each row so the weft sits flat against your scalp.
- Thread your needle and knot the end, then anchor the weft to the first cornrow by pushing the needle through the thread of the weft and the cornrow itself, pulling tight.
- Sew in a forward-and-back motion along the length of each weft, keeping stitches close together so the weft does not slip or rotate.
- Blend your natural hair over the top weft so the braids do not show, and trim the weft at the ends to match your desired length.
- A full head sew-in typically takes two to four hours the first time, and maintenance includes washing every one to two weeks and re-tightening loose wefts every four to six weeks.
Braiding Your Foundation Cornrows
Start with clean, dry hair. Use your rat-tail comb to part your hair into straight lines from your forehead to the nape of your neck. The number of rows depends on how much hair you want to add—most full sew-ins use four to six rows. Space them about half an inch apart so the weft has room to sit flat without bunching.
Braid each section tightly from the roots to the ends. Loose braids will not hold the weft securely, and the extensions will slip down within days. The braids do not need to be thick—thin, tight cornrows actually work better because they create a smoother base. If your natural hair is short or fine, you may need to use a braiding hair extension to add bulk to each cornrow so the weft has something to grip.
Once all your cornrows are done, smooth them down with a brush or your hands. Some stylists explore a light oil or edge control to keep flyaways down and make the braids easier to see while sewing.
Threading and Anchoring the First Weft
Cut a length of thread about 18 inches long. Thread your needle and tie a knot at the end. Position your first weft along the top cornrow, just below where your hairline begins. The weft should run parallel to the cornrow, not at an angle.
Push your needle through the weft thread itself—not through the hair attached to it—and then through the cornrow underneath. Pull the thread tight so the weft sits snug against the braid. Make a small stitch backward along the weft to anchor it, then push the needle through the weft and cornrow again. You are creating a loop that locks the weft in place. Repeat this anchoring stitch two or three times at the start of the weft before you begin the main sewing pattern.
Sewing the Weft Along Its Length
Once the weft is anchored, begin sewing in a forward-and-back motion. Push your needle through the weft thread, then through the cornrow, then back through the weft. Each stitch should be about a quarter inch long. Keep your stitches tight and close together—if you space them too far apart, the weft will rotate or slip sideways when you move your head.
Work your way down the entire length of the weft, staying in the same cornrow. When you reach the end, anchor the weft again with two or three tight stitches, then tie off your thread on the underside of the cornrow. Trim the thread close to the knot so it does not catch on anything.
Move to the next cornrow and repeat the process with a fresh piece of thread. If you are adding multiple wefts to one cornrow, leave a small gap between them—about half an inch—so the cornrow can breathe and your scalp does not get irritated.
Blending and Finishing the Sew-In
Once all the wefts are sewn in, your cornrows will be visible on top. Take a section of your natural hair from above the top weft and brush it down over the weft to cover it. Use bobby pins or small clips to hold this hair in place while you style. Some people leave this top section down permanently; others pin it up and only let it down when they want to cover the wefts.
Trim the wefts at the ends to match your desired length. Use sharp scissors and cut straight across, not at an angle. If you want layers, cut the wefts at different lengths before you blend them with your natural hair. Style the sew-in as you would style your own hair—blow dry, curl, straighten, or braid it.
Washing and Caring for Your Sew-In
Wash your sew-in every one to two weeks using cool or lukewarm water and a sulfate-free shampoo. Wet your hair, explore shampoo to your scalp and the roots of the wefts, and rinse thoroughly. Avoid rubbing or scrubbing the wefts themselves—this can cause matting and frizz. Condition the hair lengths, leave the conditioner on for a few minutes, then rinse.
Pat your hair dry with a towel rather than wringing it. You can blow dry on a low setting or let it air dry. Sleep on a silk or satin pillowcase to reduce friction and frizz. If a weft starts to loosen or rotate, you can re-tighten it by adding a few new stitches in the gaps, or take it out and re-sew it.
Common Mistakes to Avoid
The most common mistake is spacing your stitches too far apart. Wefts that are sewn loosely will slip and rotate within the first week, and you will have to take them out and re-do them. Stitch every quarter inch, even if it takes longer.
Another mistake is braiding too loosely. If your cornrows are not tight, the wefts will not have anything to grip, and they will slide down. Tight braids are uncomfortable at first, but they hold the sew-in in place for weeks.
Do not sew through the hair attached to the weft—sew only through the thread of the weft itself. If you sew through the hair, you will damage it and create weak spots where the weft can tear.
Avoid leaving the sew-in in for more than eight weeks without taking it down. Your natural hair grows, the braids loosen, and the wefts will start to slip. Taking it down, washing your natural hair, and re-braiding every six to eight weeks keeps your hair healthy and your sew-in find.
Frequently Asked Questions
How long does it take to sew in hair extensions?
A full head sew-in takes two to four hours the first time you do it, depending on how many wefts you are using and how fast you sew. Once you get faster, you can do it in 90 minutes to two hours. Partial sew-ins (adding extensions to just the crown or sides) take 45 minutes to an hour.
Can I sew in extensions on my own head?
Yes, but it is harder than working on a mannequin head. You will need a mirror to see the back, and reaching the nape of your neck while sewing is awkward. Many people sew the front and sides themselves, then ask a friend or stylist to do the back rows.
What kind of thread should I use?
Use thread made for sewing hair extensions, which is stronger than regular sewing thread. If you cannot find hair thread, upholstery thread or heavy-duty thread works. Avoid thin thread—it will break under the weight of the extensions.
How do I remove a sew-in?
Use small scissors to carefully cut the thread holding each weft, then gently pull the weft away from the cornrow. Once all the wefts are out, unbraid your cornrows. Wash your natural hair thoroughly to remove any leftover thread or adhesive, then condition and deep condition to restore moisture.
Can I reuse the wefts after I take them out?
Yes, if the wefts are still in good condition. Wash them gently with shampoo and water, let them air dry, and store them flat in a clean container. Wefts can usually be reused two or three times before the hair starts to shed or mat.