The Question
Just want to make sure I understand how the apprenticeship will work in regards to WWOOFing. Normally your certification program or apprenticeship has a fee right ? But for wwoofers that is waived. However you mentioned that it normally takes a year to complete. How long do I have to wwoof in order to still be able to complete the apprenticeship?

The short answer is it's possible to complete the Aromatherapy Certification Program in 6 months, but not less. I can give a WWOOFer certificate for each hour contributed, and a Certificate for each Workshop completed, but the Aromatherapy Certification Program conforms to international mater's standards, and the required workshops are only guaranteed to run every 6 months.

Your reason for WWOOFing should be a desire to contribute, to learn Apothecary operations in-depth and hands-on, and not viewed as an hour-for-hour work exchange. I do offer Work Exchange as explained here http://www.anarreshealth.ca/content/apprenticeship-and-work-exchange-application . Generally, people choose Work Exchange when they want a particular workshop or series of workshops and want to pay in labour instead of money. Work Exchangers pay the materials cost of $10 +HST per 2-hour workshop, or $50 plus HST per 6-hour workshop.

The long answer follows:
So you are speaking to Aromatherapy Certification, which is 60+ instruction hours.The curriculum is here: http://www.anarreshealth.ca/product/aromatherapy-certification-program
The Apprenticeship is a higher level of training @200-400 hours and it includes a lot more hands-on experience. The Apprenticeship Certification reflects this extra training. An Apprentice commits 4 hours per week in-store shifts, plus 2 hours per month in community outreach. Generally, an Apprentice completes the workshops in months, then does the independent work in 6 months. Roughly half of Apprentices stay longer than a year and take their time completing workshops and independent work.
WWOOFers commit 30 hours per week in store and learn all aspects of the Apothecary hands on. Unlike Apprentices and Certification students, WWOOFers also help out in the garden and harvest plant materials and learn how to process them from start to finish. As a bonus, unlike other WWOOFing volunteer experiences, WWOOFers at Anarres take any and all workshops free of charge. Several WWOOFers who have stayed 6+ months have earned Aromatherapy Certification. Each Required Workshop is scheduled every 6 months, so it is unlikely to have one come up more often unless by request. To complete Aromatherapy certification in 6 months, the WWOOFer would need to begin the independent work right away and complete it alongside the workshops. So the two parts of the certification would happen simultaneously.
If the WWOOFer ends their visit before completing the certification, as most do, they have still earned the certificates for each of the workshops they've taken. It is possible then to complete the requirements of the second half of the certification remotely and receive coaching by email and phone, or by switching to Apprentice or Work Exchange status. The only time they'd return is for the talk at the end and graduation party, or if they are far away, complete the talk requirement on Zoom or hold it in their location and record it.