I'm going based on the assumption the OPs water
is hydrophobic due to the question he asked. I very well could be wrong, of course.
Even when I completely soak my peat based soils with water prior to transplant, I still find there are "dry pockets" when I harvest the plants if and when I observe the soil in the pots. I've found that slow watering in multiple steps helps to eliminate these dry spots, but that's just my experience.
Definitely not "life or death" by any means, but I find it helps quite a bit. The majority of the organic inputs we use are in a powdered form, so they tend to clump up on you if you apply them prior to watering. Or worse, the pressure from the water makes a huge mess/waste of the top dress.
I've found that, by doing the first 1/3 of my watering and then applying my top dress, the amendments tend to absorb the water. This prevents the issues I mentioned above from happening while simultaneously allowing for a more even application of said amendments. Neem Meal is the biggest culprit of this.
@Hollatchaboy suggestion of using the spray bottle is definitely a great idea, and something I've done many times in the past when I'm only dealing with a handful of plants at a time. With more than a dozen plants it can become time consuming hitting the amendments with a pump sprayer, which is the only reason I stopped doing that. A pump sprayer will totally work wonders and achieve a similar result.
By applying amendments this way when I'm watering, I've found that I get minimal powder being blown into the air (waste), the water "activates" the amendments, and allows for more even application.
Using a form of mulch will also help even more with both watering and applying dry amendments, especially if you're using wood chips or pine needles as mulch. The first 1/3 of water covers the mulch, and the dry amendments get caught into the mulch. Not only does this prevent the aforementioned issues from occurring but will result in the mulch decomposing faster than normal, translating to free compost. Win win! Just my experience, at least.
Regards.
