You can't, you are at the mercy of the plant, just provide the proper temperature and hope for the best. I've had a mask dormant for a year! I thought it was long gone, even forgotten about it.

What is the general care of these plants? Are the conditions right that I have in my room?

Hey, there Ajacs. I noticed you had inquired about the care of your Alocasia amazonica hybrids. I don't grow this particular alocasia, and I don't grow them as houseplants. The alocasias I grow are in the garden, or just overwintering in the house until I get them planted in the year in spring (assuming they make it). Anyway, I found some culture information concerning Alocasia amazonica and hybrids that may be of some help to you, from Agri-Starts.

Growing Information

Temp: below 45F plant may go dormant
Light: 65%-73% shade, likes high light, but will do reasonably well in 80% shade
Soil: aerated mix containing bark, coarse perlite and peat moss
Mature Height: 3-3 ½'
Pot Size: 8-14"
Hardiness: Zone 9
Major Pests: Mites
(Control: Avid, Pentac, and Kelthane)
Diseases: Alternaria, Botrytis Blight, Anthractnose, Phytophthora/Pythium Rot, Rhizoctonia Root and Stem Rot, and Xanthomonas Blight
Origin: South East Asia

Amazonica is an enduring favorite that has been around for a long time. It is a watsoniana x sanderiana. It typically has leaves 12-24" long by 6-11" wide. The upper surface of the leaf is dark green and the midrib is typically a lime-white. The primary lateral veins are surrounded by white-silver zones and some clones have an extensive network of silver veinlets between the primary lateral veins. The lower surface is typically matte purple with a green-white midrib and major lateral veins. Between the laterals on the lower surface the veinlets are pale green-white. The petiole is typically 15" long and is green with dull brown variegation in the lower half. The corms are white with a tint of very pale pink.

I have to add that this is usually the dormant season for alocasias and colocasias, and while I wouldn't totally withhold water, you might want to cut back on watering some, especially since it appears your plant is not in active growth. Don't fertilize now. Wait until it begins active growth in spring. You might want to put the plant outside once the night temperatures are in the 60's, in shade. I think Amazonicas like more shade than some alocasias. I have macrorhiza, wentii, and plumbea nigra, and they can take a bit more light than Amazonica, IMO.

Anyway, for it to be dormant now sounds pretty normal to me. It may be hardy outside in your zone, but I wouldn't try that now. The bumps you noted, to me, are just part of the tuber. My tubers are kind of bumpy right at the bottom where they enter the soil, so I don't think that is unusual either. Humidity could be an issue, and you may have to deal with spider mites, a common ailment for alocasias in a dry indoor environment. Do you have a cool mist humidifier on it, or do you set the plant on a saucer of rocks (saucer wider than the pot) with water in the saucer, but not enough where the water will reach the roots of the plant? I used to just run a cool mist humidifier on my indoor plants that like high humidity environment, and that seemed to work.

Hope this helps you.

Susan

Like planty, I've had a couple of these go dormant for so long I thought I'd lost 'em, so keep 'em warm and slightly damp and be patient. As for putting them outside when the night temperatures are above sixty--I was born in Seattle and grew up about a hundred miles south of there but it's been a long time. My oldest son moved here recently from Seattle so I asked him, does it ever get above sixty at night there? He said, sure it does--for about two weeks. Folks down here can't comprehend West Coast temperatures, and folks who've lived there can't really believe ours. I think your African Masks will do fine indoors, and would probably not care for either the much lower temperatures or the lack of outdoor humidity. You might need to add humidity if you can indoors--grow on a pebble tray with water not quite reaching the bottom of the pot, for instance. I used to pour very hot water in the trays sometimes when the humidity got low. I think their leaves are better designed to tolerate lower humidity than many though.

I grow several amazonicas here in the Seattle area. I kinda think the the warm night season is too short to risk the bugs & slugs that come back indoors with them, for me personally anyway. Right now mine are all throwing out new leaves or spathes. A little bottom heat can give them a kick in pants, how bout on top the frige till you get a new leaf spike(it'll be too dry once you get a leaf)? Once a week watering at 60% humidity is risky if you don't have a very porous mix. They are very sensitvie to watering mistakes. They don't like being water logged, but they especially don't like going dry. So a really loose, open mix with plenty of air & perfect watering are ideal. Lots more light when you get your first leaf. Also maybe a very diluted foliar spray when you get the new leaf. Be really careful of overwatering a dormant bulb.

How do you get 50 to 60% humidity indoors in Seattle in the winter? You must have some kind of humidfier or you're keeping them cooler?

I'm a Newbie with a new Alocasia and its leaves along the sides are brown....I took it out that pot and changed the soil.... This is the 2nd one I've had since June whats
the care or secret to success for these beautiful plants? No water or some water....in the Sun or just a lighted room
like I have I notice it has a new leave ready to unfold but
then I find a white mildewy stuff on a leave, I treat it with insecticide and then wash the plant down..Help!!!!

You might get more specific advise for your problem if you can tell us which Alocasia you have, and if you start a new thread for your questions. If you have the same kind as discussed above, probably most of your questions would be answered there. I am personally not enthusiastic about using pesticides--usually just a good wash will take care of problems. If you have mildew a pesticide will do no good at all, tho' it's possible what you have is mealybugs. Then you're better off with an oil type spray, like Neem. (They have a waxy coat that resists sprays.)
Most Alocasias like some shade, so in the house is okay, and they like plenty of water when they're in full growth but need very good drainage--no heavy soil. When they're dormant they need less water.

I think that for those who are growing in the Pacific Northwest, and growing as houseplants, it may not be a cut and dried question of just temperature and humidity. Day length also may have a lot to do with it. Since the plant was doing okay for 2 years until it was repotted, the repotting most likely caused it to go a little into shock, and when it noticed that the days have really started to get shorter now and there's not as much light as there used to be, it probably said, okay time for a nap! You said you are using "artificial lighting". If there's any way you can get it into the sun in a really sunny window that may help it reemerge. The alocasias I have grown as houseplants all grow under a bank of 8 skylights that stretch a full 24 ft across the ceiling and are fronted by an equal 24 ft of floor to ceiling window, so they get essentially full sun (through the slight muting effect of glass) all day every day 365 days a year. They don;t go dormant, ever. In summer they go out onto the front porch and sidewalk and are again in tons of sun.

I always try to hold off repotting anything until spring, and if that's not possible I shoot for August or very early September when there's still a lot of heat and lots of daylight left.