How to Start Seed Indoors (Part 6 of 6): Transplanting Seedlings

By: Maureen Gilmer

Seedlings - Maureen Gilmer

Seedlings: All these seedlings are ready to be transplanted into individual pots.

When your seedlings begin to ramp up growth, they might not find much nutrition in the sprouting media. That’s why transplanting seedlings into containers with quality potting soil is so important. The nutrients in potting soil brings the seedling to the age where it will survive outdoors. It needs a large root system encouraged by rewards of nitrogen which stimulates rapid stem and leaf growth.

A three or four inch plastic or peat pot is the ideal size for this transitional period. You can also use recycled tin cans, yogurt cups or similar sized containers with one to three holes punched in the bottom for drainage. Use hammer and nail for tin, and a screw driver heated in the stove flame to melt neat holes in plastics. Recycle flats from the garden center, or line your pots up in a tin baking pan, TV tray or a plastic box to allow you to move them around as a group.

Because seedlings are going into an organic garden, use OMRI listed Black Gold Natural & Organic Potting Soil for these new pots. This rich blend is finely textured for young seedlings. Fill each pot with soil to an inch below the rim so there’s room to fill it up with enough water without overflow or repeated shallow fills.

Transplanting your seedlings should be done with a gentle hand. Use a blunt knife to ease seedlings out of the media without tearing roots or disturbing the next seedling in line. Use your finger or a dibble to open a hole in the potting soil large enough to accommodate the entire root system comfortably.

Plant - Maureen Gilmer

Plant: Don’t pick up seedlings by the stem; support the roots with your hand.

When transplanting tomatoes, they can be planted much deeper into this soil so new roots will form on the underground part of the stem. With other kinds of seedlings, transplant at the same depth they were in the sprouting media. Do not squeeze the stems. Always support the roots with the palm of your hand so the weight of damp media doesn’t tear them from the stem.
Once seedlings are in their new pots, water them in to collapse any air pockets in the root zone. With the nutrient rich soil, growth will speed up so your seedlings will benefit from lots more direct sunlight. Just be careful over the first few days to ensure they adapt well to the exposure without wilt or burning.

On mild days take the whole box of seedlings out onto the porch to help them become adapted to the breezes and air quality outdoors. If nights warm before you are ready to plant, leave the seedlings outdoors overnight to better adapt. Just keep them out of reach of curious pets and hungry wildlife. This transitional period is called “hardening off” which is essential in northern climates where nights of late spring tend to be colder. When grown in a cold frame, hardening off can simply be leaving the glass cover off the frame for a few nights before you move your plants into the garden.

Transplant Seedlings - 3 Steps - Maureen Gilmer



Step 1: Fill pots with soil to an inch below the rim to make it easier to water.
Step 2: When planting tomatoes, plant deep to encourage new roots from the stem.
Step 3: Press soil into the root ball but don’t compact it or you’ll damage root hairs.

This article is part of a six-part series entitled How to Start Seed Indoors by expert garden writer and Black Gold contributor Maureen Gilmer.READ MORE ARTICLES FROM THIS SERIES…

Intro: Germinating Vegetable Seeds Indoors: Get A Head Start This March

  1. How to Start Seed Indoors 1 of 6: Read The Seed Packet Before Starting Seed Indoors
  2. How to Start Seed Indoors 2 of 6: Use Clean Bedding to Prevent Damping Off
  3. How to Start Seed Indoors 3 of 6: The Right Container Helps Germinate Seed
  4. How to Start Seed Indoors 4 of 6: Sowing Your Seed Properly
  5. How to Start Seed Indoors 5 of 6: Proper Watering of Indoor Seedlings
  6. How to Start Seed Indoors 6 of 6: Transplant Seedlings Into Pots

About Maureen Gilmer


Maureen Gilmer has been a noted figure in horticultural journalism for over 30 years. She is author of 18 gardening books and writer of Yardsmart, a national column syndicated by Scripps Howard News Service. She is also garden columnist for the Desert Sun newspaper in the international resort town of Palm Springs. Maureen is a public speaker and former host of Weekend Gardening on the DIY Channel. She lives in Morongo Valley with her husband Jim and two rescue pit bulls. When not writing or photographing she is usually out riding her quarter horse.

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