Get Your Garden Ready for Frost

We have had a mild summer and fall this year on our farm in Cove, Oregon. The usual Labor Day frost didn’t touch us, but now it is the end of September and frost is inevitable–possibly tonight, September 27. Here are some tips on keeping your garden going a little longer this year.

Frost nipped the top of the pumpkin plants in early September.

Tip 1: Prioritize

Covering your garden every night and uncovering in the morning is tedious, so first prioritize what you really care about and what you can feasibly protect.

By September at latitude 45 north, no flowers will amount to mature vegetables–there just isn’t enough warmth or daylight left. Zucchini is the exception, but you might be tired of zucchini and glad to see it go anyway.

Photo by Pixabay on Pexels.com
Not all your crops need frost protection.

Anything in the Brassica family–kale, broccoli, cauliflower, cabbage–will make it. Lettuce and other leafy greens are also cold tolerant. Root vegetables are protected by stable ground heat. In my family, we dig carrots for Christmas dinner.

Many folks like to leave root crops in the ground and cover with straw for extra insulation. I tried this and even covered the straw with plastic. The mice ate 300 feet of carrots and were happy for their warm, dry home. I prefer to leave them in the ground without creating a mouse house, and have had no trouble with them freezing, especially once the snow falls and insulates them.

Basil can die above freezing–at 35F!
Crops that need protection.

Protect tomatoes, peppers, basil, flowers and any very young seedlings you planted for your fall garden. Remember–basil can die at 35 degrees or lower, so it needs extra protection.

If you bravely planted Dalias, rosemary or other crops that are marginally successful in my zone 5b, you need to come up with a plan to protect them over the winter.

And don’t forget about your potted plants. Above ground their roots will freeze, so bring them inside or dig a hole and put the pot in the ground.

Tip 2: Quicken Ripening

Our most beloved plants didn’t evolve in the northwest. They come from Mexico or Italy–Mediterranean climates. Give your plants more clues that it is time to ripen.

Your indeterminate tomatoes are probably flowering like there’s no tomorrow, but it is time to tell them the end is nigh. Hack off any flowering parts of the tomato. Pinch any flowers from peppers and keep the basil flowers pinched too. Cut way back on water so plants are “shocked” into ripening. Tomatoes need water 0-1 times per week at this point in the season.

If what you’re trying to ripen is flower seeds to save, cut off the water all together.

Photo by Richard Fletcher on Pexels.com

Tip 3: Watch the Weather

Every morning and late afternoon, I check the weather forecast. I want to know the nighttime low and weather the skies will be cloudy or clear. I don’t ready the NOAA forecast or anything fancy. User friendly weather sites for non-weather nerds are fine.

Frost is most likely to form on your garden if the nighttime low is near 32F and the skies are clear. Cloudy skies trap more heat and result in warmer nights. A weather forecast of a low of 35F and cloudy skies doesn’t alarm me as much as a forecast of 38F and clear skies. However, I always cover if the forecast is below 40F because I just sleep better.

We cover tomatoes outside the hoop houses with remay and boards keep the remay in place. We pull twine between the trellis posts to keep the remay above the tomatoes where it could get wet, touch, and freeze the plants. Photo by Evy Wallace.

Tip 4: Cover Up

Once you’ve prioritized which and how many plants you want to save, find covers you can use to keep frost off your plants at night. The idea with covering is to physically block dew from settling on your plants, freezing, bursting plant cells, and killing vegetative matter. The frost you can protect against is basically frozen dew.

Often the lowest temperatures will come after wind blows a storm through in the night. Your coverings must be able to withstand nightime breezes so you don’t have to get up at 3am to fix them.

What You Need
  • LIGHT WEIGHT, DRY coverings
    • Tarps or plastic sheeting
    • Remay, bedsheets or fabric
  • Weights or straps to keep covers in place.
    • Jugs or buckets of water
    • Boards or rocks
    • Bungees or ropes criss-crossed over covers

Testing out your frost protection system ahead of time is key. While their not pretty, I leave my coverings and weights right next to where they will be used so I can easily cover if the forecast unexpectedly changes.

uncover your plants & Keep covers dry

Especially if you use clear plastic, you can burn your plants up during the day if you leave the covers on. If you leave the covers on, the plants will get less light to ripen fruits. Also, keep the covers dry during the day. If you put wet covers on your plants, the covers themselves could freeze and freeze your plants.

Photo by FOX on Pexels.com

Tip 5: Melt Frost with Water

If the nighttime lows are forecasted to dip near 32F just before sunrise or you forgot to cover up, you can opt for spraying frost (frozen dew) off of plants before it has the chance to freeze plant cells.

In order to effectively melt the frost off and save your plants, you MUST spray it off BEFORE sunrise and continue to spray it off until AFTER sunrise.

The coldest temperatures occur after sunrise. Temperatures continue to drop until the sun is able to overcome the cooling of the earth. If you spray frost once but the temepratures are still below freezing, the water you added to your plants will freeze again. You have to use continuous water to keep the plants warmer and frost from forming. If sunlight hits tender vegetation with frost on it, it will blacken and die.

You can set up sprinklers around your garden and turn the sprinklers on in the morning or set them up on a timer to start before sunrise for frost protection. Just remember to drain your hoses every night so they are ready to use in the morning and not frozen themselves.

Photo by Anna Urlapova on Pexels.com

Tip 6: Observe Your Backyard Weather

Weather forecasts are general for your area, not specific to your garden. I have learned through the years that the forecast at my house is generally warmer by 5-9 degrees. That is to say if the forecast in Cove, Oregon is a low of 40F, it will be between 31-35F at our garden and may freeze. The forecast is perfectly accurate a quarter mile away at my friends’ house.

I have an indoor/outdoor thermometer and I keep mental track of the afternoon forecasted low versus the actual low at our house. Make sure you mount the outdoor thermometer near the ground where it is colder. Over the years, observation has allowed me to make the 39 degree rule–I will cover if the forecast is 39 or below. This rule just makes it easier to decide when to go to the enormous trouble of covering the farm.

I hope you are able to keep your gardens going through the nighttime temperature dips.

May we have a long, warm October.

Your Grateful Farmer,

Nella Mae

Fall planting and overwintering

August is usually a time when the mowing, weed eating, weeding and other garden chores ebb and the harvest peaks. A few yellow leaves off the cottonwoods are starting to fly, and the nights have that edge-of-fall chill. It may feel like harvest and canning time, but it is also time to start planting for fall and winter crops. Just think of this–for many years my dad and I have had the tradition of digging carrots for Christmas dinner. Wouldn’t you like to be eating the sweetest, brightest carrots too? If so, now is the time to plant.

Our overwintered Bolero carrots.
The Planting Season is the Whole Season

One of the biggest differences between a typical home garden and a market farm like mine is the frequency of planting. To extend the season, home gardeners can simply plant 1. small amounts, 2. more often, and 3. longer into the season.

As a market farmer, I start planting in the greenhouse in February. If it is dry enough, in April I start planting the February starts and seeds outside and in the hoop house. I consider my planting season weekly or bi-weekly from April through mid-September in my 6b hardiness zone.

Home gardeners will have less space than I have on the farm, but the concept is the same. Plant partial rows or plots weekly or bi-weekly throughout the season. Each week you can use a small hoe or hand hoe to prepare a small spot for a few feet of lettuce, beets or scallions. Spend 10 minutes planting a small space rather than putting in 20 feet of radishes. You cannot eat that many. I know the temptation once seeds get into your hand to plant until the packet is empty, but hold back!

How I Plant Season Long

As soon as one crop is pulled out of the ground, I prepare the soil for the next. I plan ahead and cut water to crops that I know only have one more picking so that I can harvest, pull, till and plant right away. I want the soil to dry out so I can till or hoe it into a proper seed bed. Make sure you remember to baby your seeds along with ample water (even if it is hand watering) through germination and into the true leave stage before you forget about them and treat them like the mature plants.

Scallions are a great fall and overwintering crop.
Pick the right varieties

If you want to expand your planting season, you need to buy the right seed. For spring you need “cold hardy” varieties. For spring you need “main crop” varieties or those that don’t seem too picky about heat or cold. For summer you need “heat tolerant” or “slow-bolting” varieties. In the fall, you return to your spring varieties. For winter you look for “overwintering” varieties or cold tolerant crops that have 120 or more days to maturity. Also, anything called “Russian” is a good indicator it is cold hardy.

If you buy your seed from companies with good seed descriptions, you will be better off. I like Johnny’s Select Seed for the very specific growing information and High Mowing and Baker Creek Heirlooms for the variety.

Use row cover & plastic

Row cover (aka cloche or remay) is a wonderful way to protect your fall and overwinter crops from cold and pests. I use Agribon 30 weight because it is the most durable. You can make hoops from number 9 fencing wire or 1 inch schedule 40 PVC thick wall pipe (don’t buy thin walled PVC.) You can make short “feet” and pound them into the ground and bend your PVC hoops over them. If you leave your row cover on all season, make sure to cover with clear plastic too. The weight of snow will damage your row cover.

Many folks use straw to protect the roots of crops they overwinter such as carrots. Some folks cover the straw with plastic too. I tried this on a 60×60 bed and made a perfectly warm, dry mouse house. They ate all my carrots. Now I just leave my carrots uncovered in the wilds of winter and they do just fine.

Photo by icon0.com on Pexels.com
Crops for fall

Think about fall crops as those you eat the leaves or roots of as a guide. No tomatoes, zucchini, cucumbers or basil. Think about eating things from norther latitudes, not from the Mediterranean or Mexico.

  • Carrots
  • Onions
  • Scallions
  • Arugula
  • Kale
  • Peas
  • Cilantro
  • Spinach
  • Lettuce
  • Cover crops

You can plant any of these crops now (mid-August) in zone 6b, but you can use the Johnny’s Selected Seed fall-harvest planting calculator to get more precise. The calculator is based on the last day of 10 hours of daylight at your latitude. In Cove, Oregon on the 45th parallel north, it is November 4th. Count backwards from there for planting dates by crop.

Here is my fall planting plan for our latitude and based on November 4th. Keep in mind, these are possible crops for each date–you don’t have to plant everything every week. One thing not on my list here are radishes. They can be planted pretty much any time after the heat abates.

Overwintering Crops

As I mentioned, carrots are great for overwintering. Look for “storage” or “overwintering” varieties like Johnny’s Bolero or Napoli. I had great luck with Bolero.

Other crops that are fun to try overwintering are kale, chard, broccoli, greens like mache & Claytonia, leeks, parsnips, and onions. Remember to pick the right variety and get all the info for best planting dates and practices. I really recommend overwintering chard.

Seeds that spring up

At the end of the season, I generally throw out a lot of pea, dill, and cilantro seed. It overwinters in the ground and comes up very early in the spring when conditions are right. It you can eat the pea shoots and young herbs in delightful spring meals you will appreciate after a long winter.

I hope this was helpful to you! Happy planting!

Your grateful farmer,

Nella Mae