Choosing the Right Soil for Your Seedlings – Green Planet Naturals

Choosing the Right Soil for Your Seedlings

Quality ingredients in seed starting and soil blocking mediums are vital to ensure that your seeds will burst into healthy vibrant seedlings. So, exactly which qualities should we look for in a soil mix for starting seeds? Well, there are a couple of things that we need to keep in mind when looking for a good seed starting or soil blocking mix. Let’s break down the seedling’s needs through the growth period and pin-point what are the important characteristics of the soil.

Seeding Soil Mixes Should Have The Following Qualities:

  • Moisture: In the early stage of germination the primary issue is moisture control.  Enough moisture is needed to sprout the seed but not so much as to cause rotting or mildew. Moisture retaining ingredients such as coco coir, sphagnum moss, and compost serve this function well.

  • Support: As the roots start to grow they will need good soil structure for stability. Volcanic pumice serves this function best. It is crushed into small pebble sizes and then mixed in various proportions depending upon the needs of the particular plant. Good root penetration and stability help support the growing new plant as it gets taller and gains more leverage. Volcanic pumice is heavier than some other similar products and therefore holds its position in the soil without floating to the top like the less expensive white fluffy stuff. It also has the ability to promote a well drained soil while simultaneously holding a bit of moisture in its porous surface.

  • Nutrition: As the seedlings start to grow leaves, the priorities shift to sunlight and nutrition.  Good compost is a commonly used source of plant nutrition but is not the only viable option available. Worm castings are becoming more popular.  Worm castings have the reputation of being gentle and easy to use.  Their nutritional value can vary widely, so it is best to purchase from reputable  company. Many people are starting to produce their own worm castings using worm farms and their own kitchen scraps.

Tips on “From Seeds to Healthy Seedlings”:

The odds for growing healthy and beautiful plants improve significantly  if you start them in a high grade seed starting soil mix. The better mixes will offer easy moisture control, hold its shape so you can confidently transplant any time you want, and provide some early nutrition for the fast growing young seedlings.

You could mix your own, but what are the chances that you would get all the parts just right the first time?  Not to mention all those partially used bags of ingredients to properly store.  Isn’t this one of the things most want to avoid? Might we suggest that you just buy a small bag of good mix and use all of it rather than having to deal with partially filled bags and clutter.  If you need more, buy another. Then spend the extra time with your healthy plants and your friends and family.


While we are on the subject of starting seeds and transplanting seedlings, it might be a good idea to talk about a couple of ways to avoid some common problems that crop up way too often.

  • Selecting the Best Seedling: There is a common recommendation to plant multiple seeds in each seeding cup or block.  But some people have a hard time pulling or discarding a good looking seedling.  Plucking out a seedling also runs the risk of loosening the soil from around the one young seedling that you are planning to keep.  Here is an alternative. This year, just plant one seed per cup or block, but plant some extra cups or blocks.  Keep the ones you want and give away or recycle the others.  This will have the advantage of keeping the lucky selected seedling roots in undisturbed contact with the soil. This also circumvents the emotional tug associated with choosing who lives and who dies.

  • Transplanting In-time: Some people are highly organized and disciplined and can follow a check list and schedule very precisely to get the seedlings started, watered, and transplanted at just the right time, but probably not most of us. One of the most common slip-ups is to not get the seedlings transplanted until they are root bound.  This happens a lot and plants sit for weeks past the prime transplanting point. Unfortunately, the extra roots help keep cheap potting soil from falling off so there is an unwitting reward for procrastination.  It is tempting to assume that the plants will be just fine once they get into good potting soil because they usually seem to recover and start to grow more roots and leaves.  However, there is the nagging question of whether the lack of nutrients in a cheap or low grade seed starting soil mix will have long term negative consequences. Such as, just because the plant grows new foliage does this also mean that it will produce good and plentiful flowers, vegetables and fruit? Might it produce veggies that look good but lack some nutritional elements because it suffered during this early stage of development?  It is probably obvious, but we will say it anyway, a really good seed starting mix will have good nutritional ingredients in the formula.  This will give the seedlings a great start and will have you covered just in case the transplanting is a little late. We recommend using high quality products at every stage to insure the very best chance of optimum growth, production, and nutrition.

  • Soil Blocking as the Small-Space Garden Solution: In the small space garden, we will usually only be starting a few plants at a time.  The Single Soil Blocker that we invented and just introduced offers an efficient and effective approach to starting seedlings and transplanting.

  • Soil Block Mix: The advantages of the soil block method for starting seeds are numerous and compelling.  The mix will usually have a couple extra ingredients since the blocks need to control moisture, hold their shape and provide nutrients, all without a container.  A good soil block mix will have sphagnum moss and coco coir to hold the moisture, volcanic pumice for strong soil structure and some compost and worm castings for nutrition.  All of the key elements that we discuss earlier are in this growing medium that is good for starting seeds AND does not crumble in your hands as you try to transplant AND has the nutritional value needed to carry longer until transplanting into potting soil.  BEAUTIFULY SIMPLE!

Since the focus of this blog space is on small space gardening, we will assume that the overall amount of soil needed during a season is relatively modest, therefore, this might present the opportunity to spring for the higher quality products.  We have the opportunity and resources available to optimize the whole growing process.  So we might as well get the good stuff, don’t you think?!

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