One of my favorite features of a WordPress multisite network is that you only need one copy of each plugin and theme. Instead of having to keep multiple copies of the same code up-to-date, you update a single "network" copy.
However, the first time you set up a WordPress network and log in, it may not be immediately obvious how to use this great new system. Let's have a look.
Installing vs. Activating
First, make sure you understand the difference between administering the network and administering an individual site.
You can access both the network and individual sites through the
My Sites menu on the top bar.
Next question: how do we actually use this system of a "network" and individual sites to work with plugins and themes? It's fairly easy.
There are two main steps to putting a new plugin or theme on your WordPress website.
First, you need to install it. You need to download the actual code, and put it somewhere that your site can use it.
Second, you need to activate it. You need to tell your site to go ahead and really use it.
In theory, your site could start using the plugin as soon as the code was available. But there are lots of good reasons to separate installing the code from activating it.
For instance, you can quickly disable a plugin without having to delete the code.
(Note: if you ever suspect a plugin is unsafe, you'll need to uninstall the code, not just disable it. Actually, you'll probably have to do a lot more cleanup work, but that's a whole other topic.)
Install on the Network, Activate on the Site
On a single site, you might not notice that these steps of installing and activating are separated. But with a network of sites, the steps are separated even more.
You install plugins and themes on the network. This makes sense, because you want all the sites to use the same copies of this code.
For themes, you must also enable the theme on the network. This doesn't make the theme appear on any live site; it only makes the theme an option in the site administration pages.
Enabling the theme for the network is pretty easy. WordPress presents you with a
Network Enablelink as soon as you install the theme.
Once the theme is enabled for the network, you must go back to the site administration, and actually activate the theme for that site.
For plugins, you don't do a
Network Enable.Instead, you have two options.
You can do
Network Activate, which activates the plugin for every site in the network.
Or, you can go back to your site administration, and activate the plugin for one or more individual sites.
Tips to Remember
Probably the main thing to remember is that when you want to install a new plugin or theme, you'll need to do it on the network. You can't install anything within your site administration pages, like you used to. Those
Add new links are gone.
Instead, go to
My Sites -> Network Admin, then select
Themes on the sidebar and install the new code.
(Side note: Drupal multisite handles this a bit differently. Usually you install modules and themes under
sites/all, but you also have the option of installing code under a particular site.)
The other thing to remember is that extra step for themes. If you forget to enable the theme, you'll go back to your site administration, and the new theme won't even be an option.
Of course, you also have to remember to activate the new plugin or theme once it's installed. But that's pretty easy.
Basically, using plugins and themes on a WordPress network adds a few extra steps. But it's worth it: down the road, you'll save lots of time keeping these single copies of code up-to-date.