One of the things that I like the most about winter sowing is that it takes the bulk of the work out of growing seeds. Instead of fussing with a bunch of equipment, you use mini greenhouses made of recycled plastic containers.

But making all of those mini greenhouses does take some time. I also get tons of questions from newbies about exactly how to do it.

So I thought it would be a good idea to show you how to prepare winter sowing containers, and give you some tips that will help speed things up for you. Here is my step-by-step process…

Preparing Winter Sowing Containers Step-By-Step

There are tons of different types of winter sowing containers you could use. But the steps for preparing them are basically the same no matter which type you choose to use.

As I said above, preparing winter sowing containers is not hard, but can take some time. Making an assembly line really helps to speed things up. So, get all of your supplies ready, and lay everything out before you start. Here’s what you’ll need…

Supplies Needed:

  • Containers
  • Scissors
  • Drill & drill bit, knife, or other sharp object

Step 1: Cut tall containers in half – This step is only necessary for containers that don’t have a removable top (for example, soda bottles and milk jugs). Use a sharp pair of scissors to either cut them completely in half, or leave a small section attached so they will open on a hinge.

Step 2: Clean the containers – Most of the time you can simply rinse the containers out. But if there’s any caked on food, then wash them with soapy water. You don’t want any food left in there, or it could stink or cause mold growth.

Step 3: Make holes in the bottom – Use a drill, knife, or other sharp object to make the holes in the plastic (more details on this below). Poke enough drainage holes in the bottom of the container to allow the water to drain out so the seeds won’t drown.

Step 4: Make holes in the top – The holes in the top are there to vent the containers so they won’t overheat, and also to allow rain and moisture in. If you use milk jugs, juice or soda bottles, you can simply leave the caps off rather than poking holes in the tops. Otherwise, add the same amount of holes in the top of the container as you did in the bottom.

How To Poke Holes In Plastic Containers

This is a very common question for newbies preparing winter sowing containers for the first time. There are a few ways you can poke holes in plastic containers. In my opinion, using a drill is the fastest and easiest way to do it.

But, you could also melt the holes, or use a sharp object to puncture the plastic. Whatever method you use, don’t put too much pressure on the container as you make the holes, or the plastic can crack.

  • Drilling holes – To make the perfect sized holes, I use a 1/4″ drill bit. Just be sure to put something underneath that you can drill into. That way you won’t accidentally damage the surface under the plastic. I use a leftover scrap piece of wood. Hold the container firmly as you drill the holes, or it could just spin around on you.

  • Puncturing holes – Some people prefer to use a sharp object to poke the holes. For example, hammering a nail through the plastic. But I’ve found this method is hit or miss, and you can easily crack harder plastics. So it’s not my preferred method.

  • Melting holes – Another method I like is to use a hot knife to melt holes in the plastic. This is a nice option if you only have a couple of containers to prepare. I heat the end of the knife over the flame on my gas stove, and it melts right through the plastic. If you want to try this, be sure to use an old knife. It will turn black over time, and have plastic residue on it.

How many holes should I poke in my winter sowing containers?

The number of holes you make depends on the size of the containers you use. You want to make enough holes so the water doesn’t pool inside the container, but not so many that it drains too quickly.

Take a look at the bottom of a standard plastic pot, and use that as your guide. Then just keep an eye on your containers. If the water is pooling, you can poke more holes in the bottom. If the water is draining too fast, then simply cover a few of them with duct tape.

Making Modifications To Containers

What if you have the an awesome container, but it doesn’t have a lid? No problem! You can make some easy modifications to turn it into the perfect mini greenhouse.

All you have to do is simply cover it with a plastic bag secured at the bottom with a twist tie. Make sure to pull the plastic as tight as you can so it won’t blow away. Then poke a few holes in it, and viola!

If the container will fit into the plastic bag, you can put it all the way inside. But make sure that you poke holes in both the top and the bottom of the bag, as well as in the bottom of the container.

Preparing winter sowing containers takes a little bit of work, but it’s easy. If you have a lot of them, then create an assembly line to get the job done faster. Oh, and the best part is that you can use many of them again next year. Learn how to clean winter sowing containers for reuse here.

If you want to learn exactly how to winter sow your seeds, then my Winter Sowing eBook is just what you need. It has everything you need to know in order to get started, and be successful! Download your copy today.

Otherwise, if you’re ready to take it to the next level and learn how to grow anything you want from seed, then you should take my Seed Starting Course! It’s a fun and self-paced online course that will make you a seed starting expert in no time. Enroll and start the course today!

Share your tips for how you prepare containers for winter sowing in the comments below.