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Seed Starting Moments with Lisa Mason Ziegler

by | Feb 4, 2023

This Seed Starting Moments series is the “whys and some of the hows” of my seed starting story.

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Seed Starting Moments #1: Why We Soil Block and Which Size to Use

My #1 tip: Keep it Simple and Stay out of Rabbit Holes created by so much Internet noise

Why start seeds in soil blocks?
1) Seed sown in the garden is a gamble – healthy transplants are a surer bet
2) Simple, more effective, and less expensive overall
3) A soil block is both the container and the growing medium
4) You can start many in a small space like a pantry or tabletop
5) High rate of germination
6) No transplant shock, plants get established quickly
7) Thinning is eliminated, sow only one seed per block
8) Earlier harvest
9) Consistently works
10) Easy to do
11) No clutter of containers to store

Which size to use?
1) I use ¾” soil blocks almost all the time
2) I occasionally use the 2″ blocks to sow very large seeds or bump up transplants

Seed Starting Moments #2: The Secret Weapon of Soil Blocking

Soil Blocking Mix Ingredients and Why the Start is So Important:

Once seeds sprout, the first few days of life greatly affect the life-long health of the plant. Living soil starts the organic biological machine and gives your seedlings the best possible environment to grow and thrive. The beginning affects the end – vigorous early growth is the foundation for superior growth later. This is why we never use sterile seed-starting soil mixes. Living soil mix is our “secret weapon”!

Soil blocks require a different mix of ingredients than growing in a container, they require dense fibrous material to form and hold the block shape, and to have good water-holding ability.

The soil blocking mix includes:
Sifted Peat or coco fiber to give body
Sifted Compost
Powdered Nutrient Mix – ours is greensand and rock phosphate

Compost is the most important ingredient in this mix! It is disease-suppressing and full of all the good stuff like bacteria, fungi, and other beneficial organisms – the guys that provide care and protection to young seedlings. Old sifted compost is best, get it now for next year.

You can make large batches of these three components and store them dry separately, then have them ready throughout the year to make some soil blocking mix whenever you need it.

Seed Starting Moments #3: Germination Tips & Tricks

Germination Tips & Tricks:
• Air temperature should be 65-70F for cool-season plants, 70-80F for warm-season plants
• Use a seedling heat mat – place warm-season plant trays directly on the mat, but put cool-season plant trays on a cookie cooling rack over the mat to slightly reduce heat
• Know whether the seed needs light or darkness to sprout and sow accordingly
• Moisture level – overwatering grows algae & mold. They don’t kill but the cause of them does.

Seed Starting Moments #4: When to Start Your Seeds

When to Start your Annual Seeds:
• Identify if your seeds are cool-season hardy annuals or warm-season tender annuals
Cool Season: plant when outdoor nighttime temps are 60F or lower for 2 weeks
Warm Season: plant when outdoor nighttime temps are above 60F for 2 weeks
• Count back the number of weeks from that period that you need to grow a transplant, varies
• Don’t feel rushed or behind, just pick up where you are in the season

Seed Starting Moments #5: Caring for your Seedlings Indoors

Caring for your Seedlings Indoors:
Grow lights are a must, run them at least 16 hours/day using a timer
• Water each morning, blocks should be moist but not sitting in water, then dry by morning
Fertilizer: add to watering can weekly, we recommend an organic liquid type

Seed Starting Moments #6: When and How to Harden Off Seedlings

How to Get your Seedlings Acclimated to the Outdoors (known as “hardening off”):
• Indoor seedlings need a transition period to get them ready to live out in the garden
• Place in an outdoor area that is protected from wind and rain
• Do this when transplants are 3″-5″ tall, focus on size rather than number of weeks
• Warm-season plants need this for 7-10 days, cool-season plants a little less time
• Good time to Pinch: if you’re going to pinch the transplants this is a good time

Seed Starting Moments #7: Planting your Transplants

Planting your Transplants in the garden or field:
• Soil tests are a MUST! Learn what needs to be added (and what doesn’t)
• Prepare your bed with 2″-4″ of compost or leaf mold
• Apply general-purpose dry organic fertilizer to the bed and incorporate
• We recommend biodegradable mulch film (Bio360) for best weed suppression
• Cool-Season transplants: to protect against varmints and wind, install hoops and row cover

To learn more about seed starting and soil blocking visit

Seed Starting Moments is brought to you by Lisa Mason Ziegler, award-winning author of Vegetables Love Flowers and Cool Flowers, owner of The Gardener’s Workshop, Flower Farming School Online, and the publisher of Farmer-Florist School Online and Florist School Online.