How to install plugins on a per-site basis on a Multisite network?

Question

Is it possible to install and activate plugins on a per-site basis for a WP Multisite setup?
I am creating a "Proofs" network for my clients where I can easily create new sites to show mockups, etc. to the clients.
Some clients require a ton more plugins than others, and I am hoping to keep things better organized.

Basically, I don't want my "Network Plugins" to be convoluted with a ton of plugins that I have to filter through when trying to activate on individual sites.

Is it possible to set it up so that I can actually INSTALL AND ACTIVATE plugins on each individual site, NOT from the Network Admin?

Answer 1

As for the install part, no, it's not possible. Installation can only be done in the Network panel. Am not finding an official quote, but I'm pretty sure that this is a no-go. But here a couple of places in the core where we can see it: [1] and [2].

From the e-book Multisite 101, there are this suggestions:

• Exclude Plugins

  Exclude plugins from appearing in plugins menu for normal user in WordPress multisite.

• Restrict Multisite Plugins

  Provides an interface similar to how the ‘themes’ section looks.

• Multisite Plugin Manager

  Allows you to manage plugin activation.

I just knew MPM, and with it, you can set 3 states for plugins: hidden, visible and active on blog creation. But it cannot be used to enable plugins on a per-site basis, like WordPress offers as default for Themes.

The current plugin version is displaying a couple of notices: one undefined variable and one deprecated function. But those are minor and easily fixed.
I've also seen that it is prepared to deal with "premium" plugins, using a third-party add-on or plugin. This can be useful for custom tweaks.

None of the plugins in the list has been updated recently, not necessarily bad, but caveat emptor.

I have one plugin that works on the Network screen to show which plugin is active where, as this info is not available in the system.

Answer 2

B/c all of the sites use the same filesystem folder for plugins, I don't think it is possible it install plugins site by site within a multisite. To make you're life easier, I'd take a look at backup buddy or ns cloner. Both of those make it really easy to clone one site to another in multisite. I prefer ns cloner, but that isn't to say I know of anything wrong with backup buddy.

If those don't help and you're comfortable in sql, you can look at copying the row in wp_option_x where option_name = "active_plugins" from site you wish to copy to the new one. That will be a shortcut to activate the plugins on a new site.

Hope that helps.