How to Prepare Your Garden for Frost or Freeze
We love the cool season around Charleston– in fact, fall is our favorite time of year to garden! But eventually we transition into winter which can sometimes be tricky for even the most experienced organic gardener.
Even though we enjoy moderate Lowcountry winters, temperatures still dip below freezing — often unexpectedly— which is why it’s so critical to know how to weatherproof your garden. Being prepared will ensure you protect your harvest.
At Rita’s Roots, we watch the forecast carefully from mid-November to March and send alerts to our clients when they need to act. Big swings in the weather can be more challenging than colder temperatures because the plants don’t have time to prepare.
Don’t let yourself be caught off guard! Take some time to prepare for frost, freezes and temperature swings by following these tips to keep your organic garden thriving. Keep reading to the very end for a bonus: how to freeze your fresh herbs so you can keep enjoying them through the winter :)
A FROST VS. A FREEZE: WHAT’S THE DIFFERENCE?
First, let’s be sure we’re clear about the terminology. A frost can happen from 32 to 35 degrees, and a hard freeze occurs when temperatures go below 32 degrees for a couple of hours.
WHEN TO COVER
Frosts and freezes settle differently in our individual yards’ micro climates. I’ve also seen temperatures dip a couple of degrees lower than estimated that particular night. Give yourself a couple of degrees of buffer and cover just in case!
Gardens near the water tend to stay a bit warmer than inland gardens.
Cold hardy plants can remain uncovered during a frost. If they’re already used to cold temperatures they can even withstand a hard freeze. But we say it never hurts to protect them with frost covers just in case.
If we’re expecting temps below 25 degrees we’ll even cover with two layers.
WHAT TO COVER
ALWAYS COVER FOR A FROST / FREEZE:
Warm Season Plants such as eggplant, peppers and basil are NOT TOLERANT to a frost or freeze – they will incur damage if not protected. Nasturtiums are sensitive too! A double cover is necessary for these plants on a FREEZE night. A single cover is suitable for a frost.
COVER FOR A FREEZE ONLY:
Cool Season Plants are FROST TOLERANT; Cool Season Plants can BECOME freeze tolerant if the weather has been cold for a while and they have had time to adapt to the cold. If we have a drastic sway from warm to freezing, Cool Season Plants are more sensitive to the cold weather.
Cool season plants all have their own tolerance levels below freezing with strawberries and brussels sprouts tolerating into the low 20s and celery and fennel not able to go much below 32.
If you’re using a breathable fabric like the ones we recommend in the video and the ones we sell through our store, you can cover anytime and leave the cover on the garden for long periods of time. Increased warmth = increased growth, so covering anytime in the 40s works too! But it is not necessary to keep the plants alive.
What about citrus? Young plants need more protection than old. Young plants CAN NOT withstand a freeze. Mature plants can withstand down to 28 degrees uncovered. If the weather is below 28 degrees, I like to double cover my mature trees just in case! If they can easily be brought indoors – do it!
PRO-TIP: CHOOSE HARDY, COLD-WEATHER CROPS
Vegetables can be grouped into two categories: tender and cold-hardy. For Fall planting in the Lowcountry, we recommend these cold hardy vegetables:
broccoli
cabbage
carrots
lettuce
radish
spinach
cilantro
As the frost approaches say goodbye to that eggplant, basil and pepper from your summer garden! They usually won’t survive the first frost (which typically happens around Thanksgiving) unless they’re covered.
If temperatures cool for a prolonged period of time, production will slow. If we get a hard freeze, these plants will die even under the frost covers.
WHAT TO USE TO WEATHERPROOF YOUR GARDEN:
Here’s exactly what we use around Rita’s Roots in our personal gardens and client gardens:
Breathable, agricultural-grade frost covers that insulate the garden 5+ degrees. Depending on the temperature, sometimes we double cover. These covers are REUSABLE so don’t throw them away if they’re in good condition!
8′ bendable fiberglass support hoops to keep the fabric off the plants to prevent frost settling burn on the foliage.
Metal landscape pins to anchor the fabric to the soil. It’s important to anchor the fabric well so the wind can’t get underneath and rip your fabric off the bed!
You can also use blankets, sheets, tarps and plastic sheets, but you must remove them daily to allow for light to get through and to prevent your plants from scorching in their “greenhouse” underneath.
WHAT TO DO TO PROTECT FROM FROST/FREEZE
Okay, now that you know when to cover, what to cover and what to use let’s go through the steps for exactly how to cover your garden beds for effective weatherproofing.
Imagine you’re making a tent over the top of your garden bed:
Be sure your plants are not touching the covering material to prevent frost burn. You can double cover to prevent frost burn as well, which is what I do with my citrus. We recommend these Frost Cover tents for your garden. They’re sold in a standard 14’ or can be cut to your custom length. You can order them, along with the support rods, hoops and pins from our online store.
To protect a 4’x8′ garden bed you’ll need:
(1) 14′ piece of fabric
(5) support rods/hoops
10 pack of frost cover pins
Create a tent over your garden, being sure to tuck all plant material underneath the tent. Use the pins to secure the fabric into the soil and be sure the fabric is taught so wind cannot get underneath and whip up corners during the night.
PRO-TIP:
ADDITIONAL MEASURES TO TAKE WHEN PROTECTING THE GARDEN FROM COLD WEATHER
In addition to making “tents” over your garden beds, here are a few more steps to take to completely weatherproof your garden.
REMOVE IRRIGATION TIMERS AND BRING INDOORS DURING A FREEZE!
*THEY WILL CRACK AND BREAK IF FROZEN*
1. Water the Garden really well to saturate the soil and insulate the roots. The water also gives off heat around your plants.
2. Mulch the garden with 1-2″ of Soil Conditioning Mulch, pine straw or yard leaves.
3. Harvest all mature fruits and plant parts if protection from the cold becomes questionable.
BONUS: HOW TO FREEZE FRESH HERBS
STEP 1
Wash and roughly chop the fresh herbs.
STEP 2
Using a spoon, scoop herbs into an ice cube tray. Add a touch of water to help them stick together.
STEP 3
When frozen, pop out of ice cube tray and store in plastic bags to use all year long. It is especially nice to pull out homegrown cilantro from the freezer in June and July when it is salsa time!
HOW TO FREEZE FRESH GREENS
All greens with the exception of lettuce can be frozen — even arugula! For this you will need a big pot with boiling water, a big pot or sinkful of cold water, tongs or a slotted spoon, quart sized freezer bags, and a sharpie.
STEP 1
Wash the greens and remove any large stems. Tear or chop into manageable pieces.
STEP 2
Submerge greens in boiling water for 30 seconds (for tender greens such as arugula) to 2 minutes (for the tougher guys like collards). I usually go for a minute.
STEP 3
Move hot greens to cold water and submerge until the heat has been removed. You may need to freshen this cold water if it gets too warm. This process is called blanching.
STEP 4
Pack into freezer bags, remove air from bag and seal. Label the bag with the type of vegetable and the date frozen. If I have a lot of one green, I will make serving sized balls or separate them into serving sized bags for single uses.
Voila! That is it. Stick them in the freezer and the process is complete!
WANT MORE TIPS THROUGHOUT THE GROWING SEASON?
Inside the Garden Growers Club, we send Garden Guides twice monthly straight to your Inbox with step-by-step instructions for what to do RIGHT NOW to help your garden reach its FULL food producing potential— including frost + freeze alerts! Memberships are good for 1 full year and you can join anytime!