I've said in the past that I use raw washed wool in the center of a needle felted project. This saves me a lot of money since pretty, clean, store bought felting wool is costly and you use so much of it.
I've discovered a new center for my wool projects... yarn! And why not, I've got loads of it sitting around in bags that I'll never use and you can certainly buy it cheaper than wool and get it locally. You can either use any old color and put a thicker layer of wool on or buy a color that matches or compliments your project and not worry so much.
Let me show you what I did. Start wrapping the yarn around your finger. I'm using acrylic here but don't use cotton yarn for this. Use wool, acrylic and blends, but test a small ball before you commit to a project.
If you don't know how to make a ball out of yarn, I'm sure there are YouTube videos on the topic. For a lemon though we aren't going for a round shape so much as an oval. This is actually how my yarn balls turn out anyway. When winding the yarn, keep your thumb in one spot. Winding around this one pivot point forms our lemon shape.
When it's the right size, felt your end in. When using yarn in this way you don't need to worry about your project shrinking as you felt, this is a very firm foundation.
Now you can begin felting your wool on. My yellow wool has lights and darks and bits of brown, orange and tan(you could add greens also). You can add these wee bits to your solid yellow wool to make your lemon more life like.
We're getting there, I paid a lot of attention to the ends of my lemon but each lemon is different!
A little brown and green for a stem.
William approves of the combination so far.
When felting the stem make it sink into the lemon a bit.