Wintersowing Tutorial: Upcycle Trash to Make Garden Greenhouses & Start Seeds in Cold Weather

Photo credit: nociveglia via Foter.com / CC BY

Photo credit: nociveglia via Foter.com / CC BY

What is Wintersowing?

Wintersowing is a method for seed starting developed by Trudi Davidoff. I first heard of the wintersowing method several years ago on Garden Web. The idea is a simple one; creating mini greenhouses out of recyclable materials to use for seed starting outdoors during the cold winter and spring months. I thought that it was a brilliant method that was inexpensive, environmentally beneficial, flexible, and allowed me to keep dirt, bugs, grow lights, and whatnot out of my home.

I also love wintersowing with the kids. We can plant a little bit at a time over the course of the season, which keeps planting fun and manageable. We talk about the stages of growth as we check on the progress of our seeds. We also discuss different aspects of plants and their needs as we create our little growing spaces (e.g., we need holes to exchange oxygen and carbon dioxide; the greenhouses hold in moisture and allow the sun to shine through, we open the lids in the warmer weather so that we don’t overheat and cook our seedlings, etc.)

Why Use a Wintersowing Approach?

There are many reasons why I love wintersowing, but the basics breakdown to cost, convenience, and success.

Wintersowing is extremely economical. The containers used are generally free and readily available. Wintersowing eliminates the need for grow lights or any special equipment. A bag of potting soil is typically my only true expense. Some years I also purchase seeds, but not always (see seed discussion down below for many resources for free seeds).

I love the convenience of wintersowing. Because I am sowing seeds in the comfort of my home across a period of weeks or months, I can do a little at a time. I don’t feel overwhelmed by my garden or a need to start all of my seeds in the same small window of time 6-8 weeks before our final frost date. I also really like the low-maintainance of the method. Once I prepare a container for sowing, it just sits outside rain or shine, and there is no mess in my home. There is no need for upkeep until the seeds sprout, and from then on it is fairly minimal. It is important to make sure that sprouts don’t dry out, overheat, or “hit their heads” on the tops of the containers, but these needs can be managed with little trouble (see resources below for tips and guidance on wintersowing). Additionally, since the seeds come to life in the great outdoors, there is no need to coddle them through a hardening off period, they re ready to plant after the final frost date in your area.

The best part of wintersowing has to be the success of the method. Since wintersowing keeps seeds contained and protected, there is little seed loss due to weather conditions or animals, as there can be with direct sowing. Wintersowing also keeps temperature and moisture conditions controlled better than indoor setups in my experience. I find that I have incredibly high germination rates with wintersowing.

What Seeds Work for Wintersowing?

In my experience, just about any type of seed adapts well to wintersowing, with the exception of plants that are notoriously difficult to start from seed under any circumstance (rosemary comes to mind). Perennial plants are very well-suited to wintersowing, but I find annuals to work great as well. I have used wintersowing to grow a wide range of annual and perennial flowers, herbs, fruits, and vegetables with great success.

Basic Steps of Wintersowing

To wintersow, you will need your potting soil or preferred growing medium, seeds, and your containers. You will also need a knife or other object for poking holes in your containers, a marker to label your containers, and possibly some heavy-duty tape and rubber bands. I sometimes also purchase paper cups to use within some of my little greenhouses.

Wintersowing is generally done using plastic, food-grade containers that have not previously held any toxic or hazardous materials (I stick with old food containers that I would otherwise recycle). You want to look for containers that can hold at least a 2″-3” depth of soil with some head space for your plants. If the container itself is not clear or translucent plastic, you at least want the lid to be a clear plastic to allow the sun’s rays to shine in. Sometimes a lid can be adapted by cutting away a portion of the lid and replacing it with plastic wrap or similar as discussed in the video.

Wintersowing will shift how you look at your garbage and recyclables. Once you figure out your preferred types of containers, friends, neighbors, and others are often more than happy to route their garbage to you. Some of my favorite containers are quart size yogurt tubs, large plastic clamshells from bulk lettuces, and traditional seed starting trays coupled with single-serve yogurt cups and reused large plastic bags. Other people are milk jug enthusiasts,

The video will give you an idea of how to use and modify your containers to create your mini greenhouses.

Wintersowing Resources

Wintersowing is supported by an enthusiastic community. There are many great places to learn more about wintersowing, ask questions, and to see the setup and successes of other wintersowing gardeners. Some of my favorites:

Trudi Davidoff has her own website about Wintersowing. The site is currently under construction but still has some information and pictures.

Gardenweb’s Wintersowing Forum is a great place to post questions and reap the advice of winter sowers of all ranges of experience and from all across the country. It is also a treasure trove of pictures about wintersowing from seed starting to planting, and for the “after” shots of beautiful gardens built from wintersown plants.

The Wintersown Facebook Page is another useful public forum for discussing wintersowing and sharing progress photos. The page has over 9,000 members. The Facebook page is administrated in part by Trudi Davidoff as she continues to share her passion for the method that she developed.

But What about the Seeds?

Of course in order to wintersow, you will need seeds. One of the most exciting aspects of starting seeds on your own versus purchasing seedlings is the exponentially greater range of plant options available to you. I love thumbing through seed catalogs looking at the beautiful and exotic plant varieties. I gravitate toward unusual colors, shapes, and sizes that I would never see at a grocery store, and are a rare find even at the farmer’s market.

Whenever I purchase seeds, I prefer to support companies who are committed to biodiversity and who are against GMO seed. If this is important to you as well, I recommend purchasing from companies who have signed the Safe Seed Pledge, indicating that they will “not knowingly buy, sell or trade genetically engineered seeds or plants.” A list of companies who have signed the Safe Seed Pledge can be found here.

I also prefer to grow heirloom and open pollinated plants to allow me to save my own seed over the years; giving me a large stash of seed to work from. See a video tutorial of how I save tomato seeds here. Saving seeds from other plants such as flowers, peppers, peas, and beans is even easier.

I also find that because wintersowing has such high germination rates for me, I waste less seed and can successfully grow older seed. As a result, seed packets go a very long way and I often have extra seed from my own seed saving efforts to share. Seed swaps are another growing trend. I have participated in seed swaps through online communities as well at through my local botanic garden. Seed swaps tend to occur in January or February to allow gardeners to start their seeds in time for spring planting. This list of seed swaps around the country can help you prepare for next year’s events. Local seed libraries are another resource for seeds. See a partial list by state here, or search online for seed libraries in your state to find options local to you.

Wintersowing Final Thoughts

I hope that you find the wintersowing method to be as exciting and useful as I have over the years. After trying and succeeding with this gardening method, I really can’t imagine starting my plants any other way. I’m curious to know if you’ve tried wintersowing before. Do you have any experiences to share? I’m happy to field questions in the comments too so feel free to ask. There’s still time to start seeds for this year’s garden.

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