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 make contributions to your Roth IRA after you reach age 70 Â½. You can leave amounts in your Roth IRA as long as you live. The account or annuity must be designated as a Roth IRA when it is set up.