The temperature in your grow room is very important for the photosynthesis of your marijuana plants. For example, low temperatures reduces evaporation through the leaves. The result is that the suction force, which takes up nutrients via the roots, becomes smaller.
Yes, you can make contributions to your IRA, subject to the IRS annual contribution limits ($5,500 for the 2015 tax year, $6,500 if you're age 50 or older). But you must keep Roth IRA and traditional IRA money separate.
You can contribute to a traditional or Roth IRA whether or not you participate in another retirement plan through your employer or business. However, you might not be able to deduct all of your traditional IRA contributions if you or your spouse participates in another retirement plan at work.