Seedlings indoors vs. outdoors


I was the one who only got one seedling my first year in hybridizing and that was a weed! Thank you for all your great replies, especially Jim Turner who supplied fantastic photos of baby rose seedlings.

This second year, other than one sunflower, I am finally getting rose seedlings! I have my seed trays outdoors where there is a wider range of temperature (I’m in the San Francisco Bay Area). My very first seedling was transplanted and brought indoors where it sulked, grew a tiny third leaf, and then died. It had light 24 hours a day, had soil soaked with diluted hydrogen peroxide, and received Henry Kuska’s remedy to give straight peroxide dropped over the leaves. Other new seedlings are still outside, where one is on its last legs after turning a strange mottled dark green color.

So, I have a few questions:

  1. Assuming one has no greenhouse, do seedlings do better outside or inside?

  2. Do new seedlings require humidity?

  3. If one leaves the dome on the tray for humidity, at what point should one remove the dome?

  4. When is the safest time to transplant.? The one I brought inside was transplanted immediately upon opening, and had only a tiny side root off the tap root.

  5. The seedling went from Scotts Potting Soil for Seedlings (peat moss and perlite) to unsterlized potting soil. Should I have used the same peat moss/perlite mix to grow it out a little?

Thank you!


Different hybridizers have different methods and would give you different answers to each of your questions. Here’s what I do - no guarantee that it is any better than what anyone else does.

  1. I like to keep seedlings indoors for at least their first couple of weeks. They are exposed to fewer fungal spores and temperature extremes indoors.

  2. & 3. My seedlings usually spend their first couple of weeks on a windowsill in my shower where the humidity is relatively high. I don’t have a dome over them.

  3. The sooner you transplant a germinating seed, the less the risk of damaging it.

  4. Use only high quality potting soil. I’ve lost a lot of seedlings to cheap soil. Lately I’ve been using a mix that is mostly Amend Patio Plus with some fine Vermiculite and Peat Moss. Whatever soil you use, don’t keep it too damp. Overly damp soil seems to increase the risk of damp-off.

Unfortunately, some seedlings do not seem to have the correct genes to grow a healthy root sysyem (i.e. survive).

Another frustrating experience that I have had is a seedling that dies right after its first flower (especially when the flower is great).

If a seedling has some characteristic that you would like to try to save, you can try an “approach graft”.


Thank you both for your quick reply. It seems like one must find the growing location that works best for them.

Thanks again,