How To: Harden Off Seedlings

We’re starting to transplant some of the more cold-hardy seedlings, such as cabbage, cauliflower, and broccoli, into the garden this week. Before we transplant any seedlings, we complete a process known as hardening off. 

In your home, your seedlings experience controlled climate conditions. They receive consistent light, moisture, temperature, and no wind. When we harden them off, we prepare them for the uncontrolled climate outside in the garden. If you skip hardening off, transplanting can shock your seedlings, meaning that they can stunted, fail to thrive, or die from the sudden changes. 

When and How to Harden Off Seedlings

Generally, we start hardening off seedlings one to two weeks before our ideal transplant date. Longer, slower hardening-off periods are usually better, so give it the full two weeks if you can. We start with just an hour or two of outside time each day and slowly increase that until the plants are ready to spend the whole day outdoors. 

Don’t place your seedlings outside on very windy days or when the temperature remains below 45°F. These conditions can shock even cold-hardy seedlings. 

Hardening Off Considerations

When we think about hardening off our seedlings, there are a few things we want to consider: sunlight, water, wind, and temperature. Below, we’ll dive into how to manage these factors as we harden off our seedlings. 

Sunlight

Your indoor lights are great for starting seedlings but aren’t as harsh as the natural sunlight your plants will face in the field. 

To begin hardening them off, set them out in a shady, sheltered location for one to two hours per day. Gradually move them to sunnier areas and increase the amount of time they spend outdoors. 

Water

Plants in the field probably won’t receive the same consistent moisture they received under your watchful eye indoors. Occasionally, letting seedlings dry out but not wilt will help them adapt. tomato seedlings

Wind

Your tender seedlings have never dealt with any wind in your house. Start them outside in a sheltered location and avoid putting them out on very windy days. While your seedlings are still indoors, you can mimic the wind by gently brushing the tops with your hand.

Temperature

Sticking seedlings out as soon as we’ve had a few warm days can be tempting, but you want to avoid damaging your plants. Don’t harden off seedlings when temperatures are below 45°F. Some plants will fail to produce if exposed to cold temperatures overnight. 

For example, broccoli may “button up” or only produce tiny heads if the seedlings experience temperatures below 20°F. These cold temperatures make the broccoli think it has gone through winter and is time to flower. 

Cucumbers and melons may also stop growing if the temperatures get too cold. Bring them in at night until temperatures stay above 50°F.

If your area is still experiencing cold temperatures, placing your seedlings in a low tunnel, cold frame, or hoop house can provide a buffer and help them slowly adapt to cooler temperatures. 

Transplanting Tips

  • Transplant on an overcast or cloudy day. 
  • Ensure your soil is loose, and add compost to the bed or planting hole.
  • Loosen the roots on any root-bound plants.
  • Water seedlings well.
  • Place mulch around seedlings.

It can be tempting to haul your plants out to the garden and put them in the ground on a sunny day. However, making the most of your plants requires a little more preparation. Hardening off your seedlings is essential to thriving crops. 

4 Steps to Preparing the Soil for Spring Planting

“In the spring, at the end of the day, you should smell like dirt.” 

― Margaret Atwood, Bluebeard’s Egg

After months of waiting, we’re finally back in the garden! At this point you’ve already done most of the prep work, selecting the perfect tomatoes for your garden, learning about your hardiness zone, and starting seeds indoors. Now, the fun and the hard work, really begins. There are many ways to improve garden soil, but these steps are the ones we consider to be basic essentials to prepare your garden for spring planting. 

Step One: Spring Cleaning

The first step is to clean up your bed. Remove any old plant material, weeds and rocks. Mow or till under cover crops. Rake back mulch away from your planting area. 

Note, if you’re starting a garden completely from scratch, you may need to remove the sod, till, or use a method like building raised beds or lasanga gardening.

Step Two: Loosen the Soil

Plants generally do better when they can easily send roots into soft soil. This is especially important for root vegetables like carrots. Many people choose to till each spring to loosen the soil, but a no-till approach can help encourage beneficial insects and microbes in the soil.

To loosen your soil without tilling, use a garden fork or broad fork to lift and pry up the soil but don’t turn it over. This loosens and creates better drainage without disturbing the soil layers. A basic spade can also work in a pinch if a fork isn’t available to you. 

Again, if you’re working with a brand new bed, you may want to take a different approach by using a tiller or more thoroughly loosening the soil with a spade or fork.

After loosening the soil, rake out the surface to break up and clumps and create a smooth surface.

Young corn plantsStep Three: Amend Your Soil

We always reccomend adding 2 to 3 inches of finished compost to your beds. Compost improves soil structure and fertility. All you need to do is spread it on the surface of the bed, mother nature will do the rest. 

While many gardeners get by without one, in a perfect world you would also have some soil test results. If you have had a soil test, you can also amend your soil based on its pH and nutrient levels with amendments like lime, seaweed, wood ash, sulfur, and other commercial or DIY options, depending on your needs.

In brand new beds, you may want to stir the compost and other amendments in to get things going. 

Step Four: Moisten the Soil

Moisture is critical in the first phase of your crops life whether you’re transplanting seedlings or direct sowing. If your soil is dry, it’s best to moisten it a bit before planting. Then you can still water in your plants and seeds as needed. 

Optional Steps

Planting is one of the best parts of gardening. So much hope goes into each bed! Follow these steps before your spring planting to ensure your plants get off to a good start.

Radishes: A Guide to Selection & Care

Radishes are often at the top of the list for beginner gardeners, and with good reason. These nutritious roots are tasty, easy to grow, and versatile in the garden and on the plate. In this post, we’ll cover the two types of radishes, growing tips, and how to use the different parts of the plant. It’s not just the roots that are edible!

Spring Radishes

These are the small, crisp radishes you may have eaten in salads. They’re quick growing and thrive in cool weather. Depending on the variety, you can have radishes ready to eat just 24 to 30 days after planting! They may be mild or a bit spicy. Below are the spring radishes we currently carry:

  • Cherry Belle
  • Easter Egg
  • Red Head (Roodkopje) Radish
  • Sparkler White Tip
  • White Icicle (Lady Finger)

Their quick turnaround time makes them excellent for succession planting. When the weather is cool, you can get a crop or two out of bed before switching to a warm-weather crop like beans or summer squash. 

Don’t let the name fool you; spring radishes are also suitable for fall planting. You can enjoy another round of fresh radishes once the weather cools off. 

They’re called spring radishes because they aren’t a good storage crop. Generally, we harvest spring radishes when small, only about 1 inch in diameter. If left in the ground too long, these radishes become woody.  However, a few varieties, like White Icicle, stand up to heat better, remain mild and crisp, and are sometimes considered all-season varieties.

Black Spanish Round Fall Radishes
Black Spanish Round Fall Radishes

Fall Radishes

You’ll also find a few radishes listed on our site and catalog as fall radishes. These radishes are larger, slower growing, and generally more starchy with a more robust flavor. They also have a much longer shelf-life. Unlike spring radishes, these radishes are daylength-sensitive and should not be sown in spring.

  • Round Black Spanish 
  • Daikon
  • Miyashige White Daikon
  • Misato Rose 

You can plant these radishes in later summer for fall or winter harvests. These types keep well in the root cellar or soil in areas with mild winters. Often, it’s best to harvest these larger radishes with a fork or spade. 

Daikon radishes are sometimes grown as a fall cover crop, particularly in no-till systems. These incredible radishes sometimes grow up to 3 inches wide and 24 inches long. Their large roots help to break up and create air pockets in compacted soil. In areas where the temperature dips below 20°F, they winter kill and decompose pretty quickly, releasing nitrogen early in the season. 

How to Grow Spring Radishes 

Sow these radishes in the spring as soon as the soil can be worked. They don’t have a long storage length, even in the ground, so it’s best to plant small successions rather than many all at once. Successive sowings can be made through May and again after mid-August. 

Sow seeds about 3/4 inch apart, 1/2 inch deep in rows 8 to 12 inches apart, and thin to 1-1/2 inches apart. For good production, water regularly, keeping the soil moist. 

Daikon Radishes
Daikon Radish

How to Grow Fall Radishes

These radishes are daylength-sensitive, so they need to be fall sown. 

Sow fall radishes about 5 to 10 weeks before the first fall frost. Sow like spring radishes but thin to wider spacing, about 4-6 inches apart.

Harvest before temperatures drop below 20°F.  You can trim the roots and store them for 2 to 3 months in the refrigerator or root cellar.

Radish Pest Issues

Radishes aren’t particularly pest-prone, but like other crops, they are susceptible to a few pests, including cabbage loopers, flea beetles, and slugs. Early spring radish crops often avoid pests because of the cold weather. You can also use row cover to prevent pests.

Diatomaceous earth is an effective organic treatment for flea beetles and slugs, while you can use Bacillus thuringiensis to treat cabbage loopers if necessary.

Cooking with Radishes

While we often think about growing radishes for their roots, you can eat the entire plant. Radish leaves, flowers, and seed pods are also edible. 

Even the young leaves can have a rough, irritating texture, but this disappears upon cooking. Radishes greens can be used similarly to kale or spinach. Try adding them to stir-fries, soups, or pesto.

Spring radishes are sometimes called salad radishes because they’re excellent fresh from the garden and are easy to throw into pasta, potato, and green salad. They’re also good cooked and tasty in recipes like lo mein or curry. 

Fall radishes are starchier and offer a more intense flavor, making them better suited to cooking. They’re lovely roasted with salt, spices, and olive oil or cooked in stews and other hearty dishes. 

The flowers can be used similarly to the greens or tossed into fresh salads to add a touch of color. The seed pods that follow them are also tasty. Some radish varieties are grown primarily for their seed pods. Like the flowers, they’re excellent raw, or you can lightly sautee them. 

Radishes Growing

How Do I Save Seed from My Radishes?

If you plan to save seed from your radishes, it’s best to isolate your varieties. Isolate a minimum of 1/8 mile for home use. For pure seed, isolate from wild and cultivated radishes by a minimum of 1/4 to 1/2 mile.

You also want to think about population size for viable seeds. It’s best to save from at least five plants for home use, but if you’re going to maintain a variety over generations, seed from 20 to 50 plants would be better.

Radishes may be annual or biennial, depending on the variety. After flowering, they produce seed pods, which become brown and dry when mature. Thankfully, they don’t split quickly, so you can wait to harvest until they’re fully dry. 

The pods are difficult to thresh. You may want to shell them by hand if you’re only preparing a small amount. Threshing radish seeds takes a lot of force. Some folks put them in tarps or old feed sacks and drive over them with a vehicle. 

Thankfully, radish seeds are usually much heavier than the chaff and are generally easy to winnow.

Saving the Past for the Future