Idaho Falls Community Garden Association

DOWN IN THE DIRT: The basics of getting your seeds in the soil

This is what you’ve been waiting for through all the dreary, cold months of Idaho’s winter. Now, finally, it will be you, the seeds and the soil. Following is a discussion of the basic considerations for successful sowing: soil preparation, seed preparation, seed planting techniques, watering and thinning.

Preparing the Soil:

Soil tilth: A friable (crumbly, loose), well-prepared soil is a must for getting your seeds off to a good start. Breaking up the soil and creating a loose, soft base for the seeds is very important. Here are three important things to remember as you prepare to do this:

You can break up the soil using either a spade, a garden fork or a power tiller. The hand tools will be better for your soil in the long run because they will not pulverize the soil as thoroughly as a tiller will. After breaking up the soil  rake it to as smooth and finely worked a surface as possible, discarding any rocks or large sticks, twigs, weeds, etc.

Soil temperature: Soil temperature is an important factor for germinating success. Almost all seeds have a temperature range in which they will reliably sprout.  Seeds planted when the soil is too cold or too hot will yield inconsistent results, wasting your seeds, time and money. The most reliable way to determine soil temperature is to use a soil or compost thermometer but it is also possible to plant by broad seasonal categories; early spring, mid-spring, and late spring. (More about this in the seed section.) You can positively affect soil temperature with several different techniques:

Soil moisture: Once the seeds are planted maintaining proper soil moisture levels becomes critical. Allowing the soil to dry out just as a seed is about to germinate will often kill the seed. (Similarly, if the soil is kept too wet the seeds will rot before they have  a chance to sprout.) There are several techniques that help keep moisture levels consistent during germination:

Preparing the Seeds

As I have mentioned before,  good seeds are more than worth the investment. No matter how careful you are with all the other aspects of seed starting you will not be satisfied with the results unless you have good seeds. Once you have your seeds and seedlings, it is time to separate them into groups depending on when they should be sown or transplanted:

Don’t get married to a particular date for planting a specific plant, like peas on St. Patrick’s Day. Using only calendar guidelines for planting is a risky practice in this part of Idaho because of the variability of the weather. One year in late March you might have 6” of snow on the ground while the next you could be experiencing record high temperatures. Look at the weather trends and month-long forecasts as you assess how the weather is progressing in a given spring - and be prepared to protect plants if we have a spate of colder-than-usual weather. Don’t forget the importance of hardening off any seedlings you have grown indoors before planting them outside.

Here are three techniques which can be used to hasten the germination or improve the vigor of your seeds:

Sowing the Seeds
Now the seeds and the soil are ready and you are going to actually get down in the dirt. The rule of thumb for spring planting is that the seed should be covered with 3 times their diameter in soil ( a little deeper for summer plantings). Firming the soil to optimize seed/soil contact is especially important. A gentle initial watering will settle the seeds into the soil and can be repeated as indicated by the weather conditions. Spacing requirements are indicated on almost all seed packets and thinning will achieve what seeding accuracy didn’t. There are a number of homemade tools which can simplify the spacing task.

Now you need to decide which seeding technique you will use:

Once the seeding is completed the seeded area should be gently but thoroughly watered. Using a fine spray nozzle or watering can minimizes the possibility of washing the seeds out of the soil.  The soil in spring is usually sufficiently cool and moist but if there is a dry spell supplemental water can be critical. Floating row cover can also help retain soil moisture while waiting for germination. (See Soil moisture, above, for additional techniques.) Water conditions need to be carefully monitored once seedlings have emerged until they have established sufficiently deep root systems.

Once seedlings emerge it is important to ensure that they have enough room to grow. Thin seedlings early and often until you have achieved the recommended planting distance. Some thinned plants, if carefully removed, can be transplanted into new spaces. Others, like lettuce and beets, can be harvested for eating even when quite small.

Transplanting seedlings
Beds need to be carefully prepared for seedling transplants, too. The issue of good soil/root contact is important and is optimized by good soil prep. Be sure to warm up soil as necessary before transplanting if the soil temp is too cool.  Water your seedlings thoroughly before transplanting. Water the generously sized hole to settle the soil before setting in the seedling. Gently pack the soil around the plant to eliminate air pockets. Water again immediately with manure tea or seaweed extract. Protect seedlings from strong winds and extremes of heat, cold and drought. Except for tomatoes, seedlings should be set out at the same depth which they were growing in their containers. Tomatoes can be set into the soil up to their first set of leaves.

Special techniques

Take advantage of early space in the garden for quick maturing or shade-loving plants that will later be taken up or shaded  by the spread of large plants. Plant radish seeds in the same row with carrots or lettuce. When the radishes mature and are pulled, thin the carrots. Or, plant lettuce in between the broccoli and cabbages. By the time the brassicas have grown together the lettuce will be finished.  Plant bunching onions similarly and pick them as they mature leaving the space for the other plants by the time they have grown large enough to need it. Do a little research on companion planting before deciding on planting partners.

 A fun activity for kids is to make home-made seed tapes for small, difficult-to-sow seeds.

· Prepare seed bed, place seed tape and cover with soil.  Water lightly.


National Gardening Association  Q & A Library - lots of great information

The Garden Gate -directory for internet gardening sites

The Weekend Gardener - individual plant guide, seasonal planning guide

Garden Web Gardening Links - a zillion links!

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