Issue 22Seeds, Soil, Sow!

We should caveat that with a whoa, there! We may be in February but we are in a northernly climate, so although we may be able to generate some heat through lights, heat mats, greenhouse or cold frames, the light levels are still low. Providing heat without enough light results in weak, leggy seedlings instead of the healthy green shoots that will go on to make productive plants.

You may be keener than a beansprout to get going but we would go as far as to say that sowing seeds too early is worse than starting them too late.
Too Little Light Most plants need at least 10 hours of light in order to grow well and at this time of year much of the Northern Hemisphere receives less than that. As stated above, too little light results in spindly seedlings which will never make good garden plants.
Too Little HeatDepending on where you are in the country, there are still months to go where the night time temperature can potentially fall below freezing. If you direct sow seeds outside too early, they could rot in cold, wet ground while they wait for soil temperatures to warm up.
Two rules of thumb to follow are to touch the soil, if it feels cold, then most seeds will not germinate. Secondly, look for any weeds growing, if there are none there, it is still too cold for seedlings. It also helps to know your soil type: heavy clay soils take longer to warm up in spring than light, sandy soils.
Sowing IndoorsFor sunny windowsill or grow light gardeners, lack of light is not a problem as adequate light will eliminate the leggy factor and help produce sturdy, well-branched seedlings. Those seedlings, if sown early, will result in bigger plants which then need to be potted up into larger containers. A tray of seeds may fit snugly on a windowsill but once potted on into individual pots, they can quickly take over your seed starting area or your entire house! This can also cost you more money in potting soil, fertiliser and pots, as well as needing to keep on top of watering, as those sizeable seedlings will need more frequent irrigation.
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If you wait and sow seeds from late March into April, the plants can soon be moved into a cold frame or greenhouse where they will form strong plants that quickly catch up.
So, when should you start seeds? It all comes down to knowing the average last frost date for your specific area. Once you have obtained this information, simply count backwards by the number of weeks required for each type of plant to be sown inside in order to germinate and reach transplanting size or to be direct sown outdoors (all of this information can be found on the seed packet).
There may be a few seeds that need special treatment before planting so look out for that when you are planning when to sow, you do not want to find out at planting time that the seeds needed a month in the fridge first.
In general, most vegetable seeds need about six to eight weeks to get to transplant size. Flower seeds will depend on whether they are annuals, biennials, perennials.
Late frosts in the north of the country are still common into May and June so if sowing outside, keep fleece handy to throw over your seedlings if frost is predicted.
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Days to MaturitySome seed packets might give a ‘days to maturity’ time. In Scotland, we live in a region with a shorter growing season so look for varieties with a shorter ‘days to maturity’ timeframe in order to maximise your blooms and harvests.
What Can You Sow Now?

Sweet peas can be sown indoors in pots that allow for their long root run (you can even sow them into empty toilet roll tubes).

Start seeds indoors of annuals that require a long growing season like lobelia, petunia, vinca, antirrhinum and verbena.

Peas can also be started indoors, again in empty toilet roll tubes to get them off to a raring start, or outdoors from late February as they are generally hardy, but do keep an eye out for heavy frosts. Be sure to choose early cropping pea varieties like ‘Sugar Ann’.

Broad beans are also hardy and can be sown outdoors from February. Exactly like peas, they can be planted in seed trays or direct-sown in the ground, ready to be picked from May onwards.

Begin chitting potatoes this month on a windowsill to get them off to a good start, ready to be planted out around the end of March.

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Chillies, peppers, aubergines, and tomatoes can be sown on a warm windowsill, in propagators, or on heat mats in the greenhouse as they need a long growing season to maturity.

Brussels sprouts, cabbage, and cauliflower can be started off indoors and salad mixes can be sown in a cool greenhouse or front porch.

Plant up a few pots or trays of microgreens for some almost instant gratification.

Some salad greens such as spinach, lettuce, and rocket are hardy enough to be sown outdoors directly into the soil in a cold frame or in a sheltered spot, to be harvested from April onwards. Providing a little bit of cover will bring crops on faster.

Plant onion sets in modules from late February to give them a head start before they get planted out.

Garlic cloves can be planted outside.

Start seeds of cold-hardy herbs like chives and parsley this month. They can go out in the garden in March or April as they can withstand cold weather.

Garlic cloves can be planted outside.

Rhubarb crowns can be planted outside, even nestled in a flower border where their colourful stalks can add a pop of colour.

Radish, beetroot, carrot and parsnip can be sown out into well-draining soil in March but will need protection from frost with a cold frame or cloche.

Squash can be sown in pots indoors in March, under protection of a greenhouse or windowsill, to be transplanted later in the season.

Remember: your specific location, weather conditions, and microclimate may affect the success of your sowings. Do check the frost forecast, and be prepared to cover or protect plants with a cloche or fleece if frost is forecasted.
Top Tip: Warm the soil in raised beds with clear polythene after weeding and raking it level. The polythene will keep the soil dry whilst still allowing radiant light to warm the surface. Do make sure to weigh it down with heavy bricks or similar to keep it in place in strong winds.
Next issue: Hardening seeds off for planting outside.Front CoverNavigationEditor's WelcomeKeder GreenhouseContentsWhat's On In ScotlandWhat's Gorgeous in the Garden?Getting to Know GalanthusShake the TreeGardening to Aid S.A.D.Jim McColl on Scotland Grows ShowThe Nettle RevolutionSpatially Plan Your GardenElevate Your Garden with Scottish-Made Elegance!Grow Your Business advertA Plant Person’s ParadisePlant SurvivorsQuercus Garden PlantsNon-Native to Native Plant SpeciesRoses – Making the CutSeeds, Soil, Sow!Scottish Bamboo Love StoryFeature Your GardenAdvice for New GardenersGrow Your Own SpecialReady to Get EdibleSowing Bell PeppersCome and Chat About PlantsStart A Veg PlotGarlic: a Clove to GrowVeg to Sow NowDIY Protection for Your PlantsScotland Grows WebsiteThe Indonesian CookDefence Gardens SchemeA Workshop in Garden DesignSoil Selection for your Indoor Plant PalsNational Trust for Scotland - RootsJobs AheadVerdant Heart5 Most Important Pieces of Advice for New GrowersScotland Grows Next IssueArchives