Transplanting Garden Starts

Once the threat of frost has passed in your locale, it is safe to transplant garden seedlings outdoors in the garden beds.  This isn’t rocket science, but there are some tips to help ensure success.

Plants that are not cold hardy and thus cannot be planted if the low temperatures dip below freezing include:

• Tomatoes
• Squash (summer & winter)
• Cucumbers
• Melons
• Peppers
• Green beans
• Pole beans
• Eggplant
• Corn
• Sweet potatoes
• Basil

WHEN

Look up planting dates in your region, but don’t place all your trust in them.  Also look at the extended forecast, and if you have access to records for the past 5-10 years, consult those as well, as our weather has changed substantially in recent years.  You can look up planting dates at:

• The almanac: 2022 Planting Calendar: When to Start Vegetable Seeds | The Old Farmer's Almanac
• The national gardening association: When to Plant Vegetables: The Garden Planting Calendar
• Your state’s cooperative extension center

HARDENING OFF

If your plants have been kept indoors at a fairly constant temperature in a somewhat pampered environment, then acclimating them to the outdoors can ensure their success when they move out permanently.  Plants can suffer shock and die or at least suffer a set-back in growth from a sudden change in their environment.  When soil temperature, air temperature, wind, insects, light, water, and more all change at once; tender baby plants can become overwhelmed.  It’s true!  Learning to be gentle with them, and with yourself and others, can lead to all sorts of better outcomes 😊

The thinking behind hardening off is to set plants outside for gradually longer amounts of time each day until the big day of transplanting.  This can be accomplished in as little as a half day or two before the transplanting day, but success will be best with a week-long period of transition:

Day 1: set out for 1-2 hours

Day 2: set out for 2-3 hours

Day 3: set out for 3-4 hours

Day 4: set out for 5-6 hours – be sure to water

Day 5: set out for 8 hours – be sure to water

Day 6: set out for 8 hours – be sure to water

Day 7: transplant

HOW to TRANSPLANT

The three biggest considerations are

1. Depth.  Plants vary in how much of their stem can tolerate being covered.  Tomatoes can tolerate a lot.  If you have spindly transplants, it’s best to cover a lot of the stem.  The stem will grow roots and adapt well.  Brassica family vegetables can also tolerate a bit of covering on the stem, as can peppers.  Squash, melons, and cucumbers don’t like having their stems covered.

Be sure to dig a hole at least as deep as your transplant.  If your soil is compact, dig more, and loosed the dirt in the bottom of the hole to facilitate new root growth deep into the soil.  The deeper the roots go, the more moisture they can reach in hot dry summer days.

2. Soil contact. You want every millimeter of the transplant’s surface dirt to be in contact with dirt when you are done transplanting.  It is important not to create any air pockets below or beside the transplant.  Place the dirt you dug out of the hole back in by crumbling it up beside all edges with gaps.  Gently press your transplant down into the dirt and push the dirt up to the transplant when you have finished replacing the dirt and snugging it into its new bed.
3. Spacing. This depends on the growing habit of the type of plant you are transplanting.  Some spread out and take up a lot of space.  Plants vary on how well they tolerate crowding.  The seed packet or catalog should be a good guide.  If you’ve seen mature garden plants of this variety growing before, envision how much space they took up and simply try to accommodate this.  Consider a cabbage plant.  In addition to the large cabbage head, there is a round of leaves larger than large hands encircling the cabbage head.  Be sure to leave space that is at least 3x the size of a cabbage for each plant – imagine drawing a circle with an 18” string encircling the transplant.  Do the same for the next cabbage plant.
4. An additional consideration is support. Some plants don’t have sturdy stems, and need support in the form of cages, trellis, or other similar supporting structures.  Tomatoes, pole beans, and peas are examples of plants that need support to keep them from trailing along the ground.  You may want to put these in place prior to transplanting, or more likely, just after transplanting (to minimize obstacles when planting).

Watch how we transplant pepper seedlings here:

Be sure to water transplants shortly after transplanting them – as soon as you can on they day you transplant them!

Our tomato seedling with supporting wires

Direct Sowing Seeds

Some seeds should be sowed directly into the soil.  These include:

• Lettuce
• Greens (kale, spinach, chard, arugula, etc.)
• Radishes
• Carrots
• Peas
• Beans
• Squash
• Cucumbers
• Melons

For some vegetables (watermelon, melons, cucumbers, and squash), direct seeding is best because their tender roots can be easily damaged by transplanting.  For other veggies (i.e. carrots, radishes, greens, beans and corn), the volume of seeds planted makes direct sowing more practical.

For best results with summer plants (peas, beans, squash, cukes, and melons) wait until the soil warms up before you sow.

How can you tell if the soil is warm enough?

There are options.  The most direct is to get a compost thermometer and measure the temperature of your soil.  Germination of seeds is temperature dependent.  That said, we never measure with a thermometer at our farm.  If you'd like to geek-out on soil temperature, this site offers a great guide on optimal soil temperature for many varieties of garden vegetables:  https://harvesttotable.com/vegetable-planting-and-soil-temperature/

Another indicator of soil temperature includes time of year.  Reference the planting guides in linked above.  You can also keep track and reference when you planted in previous years.  This shouldn't be solely relied on however, as spring weather can vary considerably from year to year.  Another indicator is to see what other plants are doing in your area.  Where we live, some folks say to wait until the walnut trees start leafing out.  An even more (but reliable) guide is when the blackberry plants start flowering.

Again, consider

1. depth
2. soil contact
3. spacing

Consider the final size of the plants to determine how far apart you want your plants to be and sow to a depth of approximately the seed size.  You don't want to bury the seeds too deep, as the plant will exhaust all the reserve energy in the seed before the seedling leaves reach sunlight.   Cover seeds with a light layer of loose dirt or vermiculite.  For tiny seeds such as kale, carrots, and lettuce, we use vermiculite.  For larger seeds such as beans and corn, we pinch the dirt over the seeds.

Check out this short clip to see how we plant green beans seeds:

https://youtube.com/shorts/Xq9vqWS3uhQ?feature=share  

Here is how they looked about 10 days later

We advise sowing extra &/or holding back some seed.  Why?  Seeds sown outside are less protected and could be eaten by birds or other critters. We've lost an entire field corn crop to crows, and this year we lost every one of our sunflower seedlings.

Again, be diligent about keeping the seeds moist until they germinate! The tiny roots are very short and aren't deep enough to get water from much deeper than the soil surface, which dries out fast in the sun.

Once your seedlings have put on 2 to 3 true leaves, pull out any extra plants (this is called thinning, and something else that we're terrible at).

Happy planting!!