I'm not sure that there are any good preventative treatments/sprays for the soil but using mulch to keep water from splashing up from the soil onto foliage can help avoid some problems. Also, having plenty of organic matter in the soil can help keep plants stronger/more able to deal with problems. There are some rust problems that have little/nothing to do with soil.

I hope some one with more experience about ferns and rust will chime in to help you with your problem.

Good luck

As I mentioned in your other posts about the fern, I doubt the problem is rust. Instead, most likely short of water in the original rootball.

Link to one of your other posts.
http://forums.gardenweb.com/forums/load/pests/msg091221103610.html

Beyond that, you don't treat the soil even if it is rust. The spores are airborne.

Here is a link that might be useful: another of your posts.

I'd agree that the problem is unlikely attributed to rust. This fern needs consistently moist soils and high humidity to thrive and absolutely cannot be allowed to dry out. Any drying or browning of the fronds is likely due to insufficient moisture. I'd not be surprised at a water issue transferring a containered fern to an inground setting under a tree - the tree roots are just far more aggressive and successful in obtaining moisture from the soil than the significantly smaller root system of the fern. The "rust" looking substance you see are probably spores - many ferns will produce ripe spores and disperse them at this time of year.

The single most common cause of problems on any transplant is lack of water. Plants that have been growing in pots and then are transplanted to the garden are very susceptible to this because the root ball wraps around and never moves out of the pot area (pot bound), even in the ground, i9n search of moisture and nutrients unless the root ball is "broken", the roots are loosened up to encourage them to move out. As Jean has stated this is most likely what happened to your fern.

I don't know much about ferns, but I can tell you that rust is not usually a problem for plants per se. In fact, plants need a stead supply of iron to stay healthy. If you are actually seeing rust in the soil, though, that could be an indicator of low pH. Do you have a pH test kit? If not, I'd recommend getting one. Better yet, spend $20 for a pH meter, which is a lot more accurate.

-Diggity

Diggity, I do believe the OP was inquiring about the fungal problem commonly known as "rust", not iron oxide :-) They do bear a visual resemblance, though, as fungal rust looks like little rust colored bisters on plant foliage.

Ahhh, sorry, I should have read more closely. Thanks gardengal!

-Diggity

Hi!

This is to tell everyone who had responded to my question on the problem my fern was having: Thank you!

My fern seems to be doing better now.

Two days after I had posted my question on the fern forum, I dug my fern up. I didn't think I had a lack of H2O on my hands, because I would water it every other day for five minutes each time. The problem was that I was actually giving it too much water.

When I had dug it up, I couldn't believe how easily it came up. My soil is mostly clay with some small amount of sand. I was truly expecting to feel like I was pounding against a wall with my shovel, but, no. The shovel went into the soil like I was slicing butter. That was the quickest I had ever dug anything up in my yard.

Anyhow, I re-potted the fern. I had clipped off the affected fronds, and just left it alone for close to a week.

I had examined it today. I am happy to report that there are five (5!) new fronds that are coming up from the middle of it's trunk.

Thank you to all who had responded to my previous post.

Sincerely,
mbluetyphoon