Mine is outside, in full sun except a couple hours mid-day. When it was cold (and inside,) it was in a south window

Let's set aside the idea that when a plant has chlorotic foliage, the first thing we need to do is reach for the Epsom salts or Fe (iron) chelate. In a very large % of the cases, the practice is more apt to be limiting than a benefit. If you are using a commercially prepared soil or made your own and used lime when you made it, a Mg deficiency would be extremely unlikely until the plant had been in the same soil for, at a minimum, at least 1 full growth cycle and half of the next. Fe deficiencies due to an actual absence of the element in soils are also rare in containerized plants - more likely would be a pH issue that can easily be resolved and the Fe already IN the soil made available.

Additionally, everyone has the idea that a green plant is automatically healthy. You can make a plant green by adding Fe and sometimes Mg, but you may be masking other symptoms that will go untreated because all is thought well. Also, applying Mg w/o applying Ca can create an antagonistic deficiency of Ca, and excess Mg makes P and K more difficult for the plant to take up. You should have good reason to suspect a deficiency of any single element, and have excluded other possibilities before applying an element or compound aimed at supplying only 1 or 2 nutrients. In most cases, you'll do more harm than good.

If you haven't fertilized all winter and have been flushing the soil when you water, the plant is probably starved for N, and the symptom of chlorosis in older foliage is a tell. It's likely the plant is robbing N from older leaves to satisfy the N needs of new growth, and will eventually shed the old leaves. Also, tight roots cause shedding of older and interior foliage, so your plant might be telling you it wants a repot.

I would eliminate over/under-watering, general nutritional deficiency, and being root bound, before I would make any decision about adding Epsom salts or an iron supplement.

What are you using for fertilizer? last repotted?

Al

Ok, I DID "pot up" last summer because the plant was top heavy and would dry out very quickly. I only went one size larger. I was using MG, but now have Dyna-Gro to use this growing season.

So you think it needs more N?

Yes - especially if you were flushing soil regularly when you watered.

Al

Thanks, Al! And Happy Belated Birthday! Hope it was a good one. :)