Tools and Techniques- Direct Sowing versus Transplanting

So many people tell me that they buy expensive and delicate transplants since they can’t get seeds to germinate. Hearing that makes me sad since growing from seed has so many advantages over transplants but unfortunately a lot of seed in circulation is of such poor quality that even an expert gardener would struggle to make any use of it. Vegetable seed is a niche industry that is primarily oriented towards commercial growers. These farmers can produce the perfect input intensive conditions to plump and primp the crops so that they grow rapidly and produce enormous yields (often at the expense of quality of the produce, and often prioritising qualities like ease of shipping over flavour or nutrition). These varieties are often unsuited to the home gardener where conditions are usually much less than ideal. To compound the challenges of the home gardener the seed sold in small packets to them is usually the older or second rate material that no commercial vegetable farmer would ever accept. A farmer planting acres of crops at a cost of many thousands of dollars can afford to demand top quality seed that is strong enough to germinate well. A home gardener who buys a packet for $4 of seed that is dead before they buy it usually blames their own inexperience when it doesn’t come up. Disappointed they turn to expensive seedlings so they at least get a brief sense of accomplishment after putting them in.

By contrast direct sowing seeds is one of the easiest jobs I have on the farm, provided the right ingredients are in place. Firstly the seed needs to be strong and sufficiently fresh. Seed strength partly depends on the species and variety, and the ability to germinate strongly is another trait that can be bred into (or out of) crops depending on how they are grown and selected. It also depends on how well the parent plant was grown, but seems to depend more on mineral nutritional status more than anything else in my experience. How the seed was processed and stored also has a big effect, with seed kept warm and/or wet running out of strength more quickly. Some species like parsnips are notorious for rapidly losing viability even when stored perfectly, and the whole carrot/parsley family isn’t far behind in this trait. I will do a post on my seed saving techniques in the future.

The next most important ingredient for direct sowing is timing. Different species require different conditions not just for germination but to carry them through to cropping (and beyond to seeding if desired). With Australia’s highly variable climate it isn’t enough to simply use the date on the calendar to tell you when to sow each species. The ideal earliest sowing time for species can vary by a few months in different years for me under extremes of weather, though normally it varies by a few weeks. During prolonged droughts sometimes a season will be missed altogether. With accumulation of experience from trial and error you get a feel for when particular groups of species are worth sowing. Relying on signs from other plants growing or flowering can be an indicator but I find I just get a feeling that the time is right when the weather shifts in certain ways that are difficult to put into words. Sometimes I am wrong when anticipated follow up rain doesn’t arrive in time.

The final condition is the state of the soil. As I have outlined in previous posts vegetables will grow reasonably well for a home gardener in soil that looks nothing like the stereotypical crumbly black stuff in everyone’s imaginations. Under less than ideal conditions the range of suitable crops will be less than what people are used to in the supermarket, and the growth will often be slower, but the resulting produce will have a wild intensity that indicates it is full of the flavour and phytochemicals usually lacking in the bloated industrial produce in the shops. Microscopic weed seeds are quite capable of germinating and growing in the most difficult conditions, though individual weed species specialise in specific types of difficult soil. Likewise with trial and error a home gardener can find the crops that grow sincerely in the soil that millions of years of geological history has provided them. Having a supply of strong seed and the techniques to sow them directly is an essential part of figuring out this puzzle for your particular space.

There are two basic techniques I use for direct seeding in my cracking clay during typical dry spring conditions. Sowing in loamy or sandy soil is easier in most aspects. For most plants that need a fairly wide spacing (say over 30 cm apart) I use a small hand trowel to prepare a spot. I push it halfway in and lever out a few clods of clay, smack them to break them down with the back of the trowel. I use my fingers to crumble the surface soil a bit more. If your clay is so dry that you can’t do this with a trowel then a slightly larger hole can be made with a shovel with better leverage, with the blade used to repeatedly break up the clods in the hole. Under such dry conditions it is advisable to space the plants further apart to reduce water stress. You can always interplant later if the weather turns wet. I prefer to create a large number of these prepared holes first then shift to planting seeds. This reduces time repeatedly picking up tools between holes, opening seed packets again, and reduces dirt getting back into the packet. For larger seed I use the trowel to push aside some crumbled soil, then push it deeper to lock it in place. I then place the seed in the hole. The larger and more reliable the seed, the fewer I plant. The more scarce the seed the fewer I plant. Usually for large seed like legumes and cucurbits I plant 2-3 seed, thinning to one as they grow. I then remove the trowel and allow the crumbled soil to fall back over the seed. For smaller seed I simply sprinkle on the surface then stir the soil lightly with the trowel or my fingers. For crops that are better sowed in continuous rows like carrots or shallots I use a hoe to dig a shallow trench, leaving the broken up soil aside toward the path, sprinkle seed along the row, then hoe the soil back on top. If the soil is too heavy to crumble easily I will source a bucket of soil with better tilth and texture to sprinkle on top of the seed, though this can introduce new weeds into the space.

A far less preferable option is to start seeds in pots and then transplant later. For some crops that don’t mind root disturbance as much transplanting during a wet season isn’t too stressful. But for crops in the opposite camp, like cucurbits transplanted during the dry spring, the process is annoying. The only reason I sow in pots now is due to the seed being newly purchased, which means I have very small quantities (making direct sowing a risk of losing it with no result), with uncertain quality (meaning I could be wasting a prepared bed for a season waiting for it to not come up). For new species it also means I don’t have any feeling for the best timing for sowing either. This year I started a few new strains of rockmelon in pots, along with the last of my pure janosik watermelon seed that is very old and mostly unviable, and some pure Seminole pumpkin that I only have limited amounts left. These germinated as expected, sowed in individual pots into a good quality seed mix with an inch of uncomposted goat manure in the bottom of each pot. Once the rockmelons reached a few true leaves I waited for a cloudy day and transplanted them out onto the moderately loamy soil on the creek flats. Around the same time I direct sowed watermelon seed from an earlier variety trial that I had decent amounts to spare beside them. The watermelon seed were watered once by hand, mostly to settle the soil and make it less appealing for mice to dig up the seed. The rockmelon seedlings were also watered then, but needed more waterings every 2-4 days for the next few weeks depending on the weather. Sometimes little loose piles of twigs and leaves can be built over the transplant to provide temporary shade.

Carrying 30 L of muddy water by hand isn’t fun. The transplants were frequently found half wilted and a few didn’t make it. Within a week or so the watermelons were germinating strongly with no sign of wilting despite no further watering. Interestingly leaf eating beetles arrived and started damaging the rockmelon transplants while ignoring the direct seeded watermelons (though I have seen both species attacked before). I usually crush them since the damage they can do to small seedlings is considerable, versus the fairly minimal effort to stop the first few pairs breeding. After a few weeks the watering and pest control will stop. If the rain doesn’t come I will count the crop as lost and plant something different later. Better to spend a few dollars on seed again next than haul many hundreds of litres of water for a substandard result anyway.

I also direct sowed bush snake beans, okra and rosella in the hard clay soil of my vegetable garden, that have since germinated strongly despite receiving no irrigation at all (with only 30 mm of rain in October with occasional mid 30 C days, and virtually no rain through winter), while cucumber seedlings transplanted beside them are struggling despite being irrigated. They will grow fairly slowly until the rains arrive, then explode as the top growth catches up with the root system built up during the dry time. The simple mental picture of pouring water on the soil and it going into the seed to make it grow is inadequate as I have seen seed germinate just fine in apparently dry soil with zero rain or irrigation. Watering seed to “make them grow” is simply unnecessary, as it watering the crop itself, provided you are willing to experiment and accept some limitations in your garden (in exchange for one less job, one less expense, and a whole lot less weeds that love irrigation more than vegetables do). If conditions are adequate to carry the crop through production then they will be adequate to get the seed going.

The key here is the connection between the plant and the soil. Just as a human organ transplant requires many hours of delicate microsurgery to be integrated into the patient, but still never works quite as well as an original that grew in place, transplanted seedlings need to go through a difficulty process of connecting their root system to the soil around them that direct sowed seedlings completely skip over. Learning to tap into the power of seeds lies at the core of good gardening. I hope sharing these experiences encourages you to persist with mastering direct sowing and wean yourself off expensive and flimsy transplants.

A trio of bush snakebean seedlings, direct sowed in unirrigated dry clay.

A trio of okra seedlings in the same unpromising soil.

Rockmelon seedling transplants flopping before yet another watering.

Direct sowed watermelon germinating strongly with only a single light drink.