Tuberous Begonia Question

I bought four large tubers in March and settled them in damp potting soil/peatmoss with their "eyes" pointing upward. Not much, if anything happened. In late April I put them in the ground and covered then lightly with soil and mulch. I watched daily, but there was no sign of growth. Finally, yesterday, I moved away mulch and soil to see what the story might be. Three of the tubers had fairly large "eyes" (clearly much bigger than when they went in the ground. The fourth tuber had no "eyes" but seemed to be firm and in good condition. I have left the tubers in the ground, but partially exposed to light (i.e., without much covering from soil or mulch), thinking that the light exposure might stimulate development. I would welcome any input/advice which bears on this situation.

Just keep doing what you are doing.
It is still cold in your area, I bet. They will grow with time and heat.
I just place them on top of the soil and put dirt around the edges. Don't really put them far into the ground.
Carol

Sometimes it can take a very long time for tuberous begonias to sprout. I pre-start them indoors in pots with 70F bottom heat. Until soil warms in your area, it is not going to be fast.

I would cover them with atleast 1" of soil because tuberous begonias form roots on all surfaces of the bulb and if you do not cover it, it will not form roots.

Just continue to keep the plant just moist (but not wet) until the sprouts are 3-4" above ground. Then you can water more regularily; and start to fertilize.

Hi fc, I agree to keep doing what you are doing and I also agree that starting them indoors with a heating mat is ideal. Had one left from last year and never even took it out of it's pot. I just wasn't crazy about it. Drenched the pot and put it on an old kitchen saucer on the heating mat in early April. Now it's in the garage hardening off and must be at least 6" tall and so healthy looking. Try not to water into a corm: water from the edges or put it in a pie plate (aluminum disposable ones are fine) or saucer and let it soak up tepid water (and some weak Miracle Gro) and it will love you.