It’s Spring and I know you’re ready to get out there and plant since it’s sunny (wait… now it’s cold and raining…. wait! It’s sunny again… wait… ), but some vegetables won’t be happy (and grow into incredibly prolific tomato producers - yes, I’m talking to you, tomato fanatics) if you don’t protect them until night temperatures warm up consistently to 50 degrees and above.
This doesn’t mean you can’t plant them right away - you can! But you should avail yourself of several excellent tools that allow you to get them in the ground and also keep them warm and happy. Most of us at Swansons swear by these products so we can plant our warm-season vegetables earlier and encourage larger, stronger plants and better harvests.
Note: If you don’t plan on planting your tomatoes immediately, we recommend you bring them inside each night until you plant them, then protect them outside after planting.
Here are two great protection options. At the end of this post, you can also find a quick comparison and links to more information about growing warm-season vegetables like tomatoes, peppers, and squash!
Option 1: Insulated Plant Protector
An insulated plant protector (sometimes known as a Season Starter™) is a ring of vertical plastic tubes filled with water to form a warming enclosure around an individual tomato plant (or another warm-season veggie like a pepper). The sun naturally warms the water during the day and the water inside the tubes stays warmer than the surrounding air keeping the soil and your plant toasty, like it’s surrounded by a cozy blanket.
Sunlight can pass through the light-colored plastic and light, water, and air can enter through the open top. Once the flowers begin to form, the open top also allows for pollination.
It’s extremely helpful to fill and place your plant protector where you will be planting 3-4 days ahead of time so it can warm the soil a bit.
When growing tomatoes, we recommend that you use a tomato cage to support your plant. It's best to put the cage inside the protector when you first plant. Otherwise, you risk damaging the leaves and branches. The tomato will naturally grow up into the cage and you can arrange the branches easily to rest on the cage supports as the plant grows.
Once night temperatures increase in the late spring or early summer, or if the plant begins to outgrow the protector, you can simply it roll down to the base of the cage (releasing the water as you roll) and leave it there for the rest of the season. I sometimes roll mine down a little at a time as the plant grows so the base and soil remain warmed.
When the season is over, rinse out and empty the tubes. Allow it to dry upside down and store it inside until next spring. I’ve been able to reuse mine at least 3 times before needing to replace it.
Option Two: Harvest Guard®
Harvest Guard® (also called row cover) is a lightweight fabric that can help warm the air and soil. If placed over a plant, leave enough fabric so the plant can continue to grow (it will push the fabric up as it grows), or use some sort of support to keep the fabric off the plant. When wrapping a tomato cage, it can be helpful to clip the fabric as you go, using clothespins or other clips. In order to keep as much heat inside as possible, I recommend that you cover the top of the cage as well. Harvest Guard® comes in multiple lengths and widths. Simply cut what you need as you use it.
Since Harvest Guard® is lightweight and light in color, it will allow air, water, and sunlight to pass through. Once the plant starts forming flowers, you will want to open the top or unwrap the cage entirely during the day to allow pollinators access. If night temperatures are still cool, you can rewrap each evening.
Tomato cages wrapped in row cover fabric.
Photo: giantveggiegardener.com
When you remove the fabric for the season, shake it out and store it in a protected place. If you are careful with it, the fabric can last several seasons. Toss it if rips or holes form.
One disadvantage to Harvest Guard® is that it will not keep your plant as warm as the insulated plant protector. But it can still offer protection from frost and cold damage, and it is easy to work with.
Which Product is Best for You?
Both products are extremely helpful in extending the growing season and protecting your plants. Here’s a quick rundown of the advantages and disadvantages of each:
INSULATED PLANT PROTECTOR
Advantages
Keeps plants the warmest
Durable and Reusable
Disadvantages
Takes some set-up
Plants can outgrow it*
Harvest Guard® Fabric
Advantages
Is easy to set up and remove
Covers the full height of the cage
Disadvantages
Doesn’t warm as well
Needs to be opened for pollination
Less durable
*Generally, by the time they have outgrown it, the weather has warmed enough to remove it.
I’ve used both methods and they have both worked well. If I plant my tomatoes and peppers early, I like that the insulated plant protector keeps them nice and warm. If I plant my tomatoes and peppers later in spring, or if temperatures aren’t too cold, I like the ease of Harvest Guard.® In fact, I’ve sometimes used both in an especially cold spring/early summer. First the protector, and then, as the tomato plant outgrows it, I’ve wrapped the cage with fabric.
Here’s more detailed information on How To Plant a Tomato and Growing Warm-Season Vegetables in the PNW.
Remember, if you have questions, you can always ask us in person, on social media, or by email!
This post was updated for 2024!