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Sowing, planting and spacingSpacingHow to sow When to sow Seeds last for years Thinning out Transplanting SpacingWidely spaced plants grow bigger and produce more than crowded plants, but if plants are spaced closely together there will be room for a greater number. The best spacing is that which gives the biggest harvest (or the best quality). In the vegetable gardens that I have seen overcrowding is more common than to wide spacings. In the beginning of the season it looks green and promising. Unfortunately the harvest will often be a disappointment. Overcrowding also reduces ventilation, and creates moist conditions suitable for slugs and many plant diseases. Moreover it interferes with weeding and pest control.You can get some idea about the appropriate spacing by reading on seed bags. Often it is suggested that the spacing between rows should be far wider than the spacing within rows, but the only reason to have wider spacing between than within rows is to provide space for walking. Using beds it's far better to have similar spacing between and within rows. If the recommendation is 50 cm between rows and 10 cm between plants I'm likely to change that to 25x20 cm. The plants will have the same space, but stand further away from their closest neighbour. Sometimes the extra spacing suggested between rows can simply be ignored. A lettuce head will typically occupy 30 x 30 cm, but the recommendation may be 50 x 30. For the gardener using beds these extra 20-cm between rows is a complete waste of space. The table below is a general guide to plant spacing, but the space required can differ widely depending on variety. Kohlrabi will usually do fine in 25 x 25 cm, but some giant varieties need a spacing of as much as 50 x 50 cm. Not all plants will grow equally well in all soils and the spacing may have to be adjusted to local conditions. In my soil French beans do particularly well and I have found that a slightly wider spacing than recommended gives maximum yields. The figures in the table below and on seed packages are exact, but there is actually a range that will work. It is only when you deviate a lot from the recommended spacing that yields are going to drop dramatically. Spacing also depends on preference. If you like your carrots small, reduce the spacing and you will have more, but smaller carrots. To produce large specimens give your plants lots of space. Try to find out what works best for you in your garden.
Top How to sowPotatoes, Jerusalem artichoke and onion sets are likely to produce one plant for every tuber or bulb, but seeds will not. In the worst case a hundred seeds will not produce a single plant.How many seeds that are needed to obtain an adequate number of plants vary depending on the skill of the gardener, the condition of the soil, pest populations and time of sowing. Random effects like the weather will also influence the result. The disadvantage of sowing to thickly is that seedlings growing very close together can be difficult to thin out without doing damage to those left in the soil. In my experience larger seeds are more likely to produce an established seedling than smaller ones. Sowing squash, French beans and peas I use tree to four times more seeds than I need plants. When I sow small seeds I sow more. I also sow more seeds if seedlings are difficult to transplant. This is the case mainly for root crops like carrot and scorzonera. Most other vegetables can quite successfully be moved to fill gaps in the rows. Some seed e.g. Swiss chard is very unpredictable in my garden and I sow lots of these even though the seedlings are very easy to transplant. Many seeds will germinate better if they are soaked in water for 12 to 24 hours before sowing. A disadvantage of this method is the irritation that may result when wet seed stick to fingers and to each other. Life will be easier if you put the wet seeds on absorbing paper for a few minutes to soak up excess water. Water well before sowing and spread a thin layer of wood shavings on top of the soil afterwards to conserve moisture and to prevent the crust forming action of water drops falling directly on bare soil. The combination of rain and sunshine may otherwise form a crust on the soil surface, which is so hard that seedlings can't break through it. You can also use spun-bonded polyethylene for the same purpose. Spread a very thin layer of straw to keep the polyethylene just of the soil or use wire hoops. Larger seeds like peas, bean and squash should be buried under 3-4 cm of soil whereas small seeds e.g. lettuce should be just beneath or even on the surface. The easiest and fastest way to sow seeds is to take 10-15 seeds between thumb and finger and twiddle the fingers gently. After a little practice the seeds will fall one by one into the drill. Firm the soil gently, but a little harder if it is dry. After sowing you really have to watch closely over your vegetable garden. Seeds are often eaten by birds. Birds are particularly fond of beans and peas and these beds must be covered for protection. Use wire mesh or spun-bonded polyethylene. Potato beds are prone to be excavated by crows. If this happens put the potatoes a little deeper. If the soil is too dry, wet or cold seeds may fail to germinate. If they germinate seedlings may fail to reach the open air if there is a crust on the soil surface. If they manage to break through there is always the risk that slugs will attack and finish them of very quickly. Many gardeners will not be aware of what's going on. When the result is nothing they will conclude that the seeds were bad. Sometimes they are right, but more often they are wrong. Top When to sowOften gardeners try to sow as early in the spring as possible. There are several reasons for this:
In the spring of 2002 I discovered that the scorzonera and salsify sowings were a bit of a failure, but I saved the situation by sowing summer carrots in the gaps. The limits to early sowing are determined by two factors. The soil temperature must be adequate for seed germination and seedling must be able to survive the soil and air temperatures, which can be expected when they emerge. Minimum germination temperatures are linked to the tolerance of seedlings to cold weather and frosts. Seeds that need high temperatures to germinate will often rot if sown to early, while the earliest seeds will generally survive the freezing cold of winter. A few seeds e.g. lettuce, celery, parsnip and spinach may not germinate if the soil is warmer than 20oC. Seed package recommendations on sowing dates are often inaccurate. You may be advised to sow in April or May. There is often a more precise recommendation on soil temperature, but unless you know how to measure soil temperature this figure will be meaningless. Soil surface temperature typically has a greater daily variation than air temperature, and soil temperature vary greatly with depth. Soil temperature is also (as is air temperature) a relatively poor predictor of the weather to come several weeks later when seedlings emerge. To be able to pick the best sowing dates in your garden you must now what temperatures to expect and when the last frost is likely to occur in the spring. The World Meteorological Organisation is a specialised agency of the United Nations and provides climate data for many locations worldwide. The site also provides links to the National Meteorological Services of the 185 States and Territories that are Members.Low air (and soil) temperature is a reason to delay sowing, but an unexpectedly warm period early in the season is not a reason to sow earlier because this may put the seedlings at risk of to low temperatures later. You should also consider your microclimate. If your soil is wet and shaded in the spring you should delay sowing by up to two weeks, but if your garden is sheltered, sunny and has a well drained soil you can sow earlier than dictated by the general climate of your region. My plots are located near the Baltic sea, which we in Sweden call the Eastern sea (in Swedish of course). The sea influences the local climate and reduces the risk of late frosts. The daily mean temperature rises above 10 degrees Celsius in mid May and frosts very rarely occur after the end of May. Gardens at high altitudes, inland location far away from large bodies of water or in arid areas are more exposed to late frost at the same daily mean temperature. This may also be the case for gardens at the bottom of walleys or other depressions in the landscape. Late frosts are mainly a threat to frost intolerant vegetables. If your garden is frost ridden you should take measures to protect these vegetables. When it comes to warm-season and frost sensitive vegetables you should try to fit the growth period into the warmest part of your season. If the warm and frost free period isn't long enough you have to use the cold weather gardening techniques described in the next section of this guide. Many vegetables grow and mature best at not too warm temperatures. Some of them e.g. Brussels sprouts and turnip may even benefit from a light frostbite at the end of development. In Sweden the entire growing season is a cool season. In Stockholm the daily mean temperature peaks at a mere 18 degrees C in the second half of July. The best you can do under these circumstances is to get all vegetables started as early as possible to stretch the period when fresh produce is available. Only a few crops that take a very long time to mature will have to be sown indoors or started in cold frames. This includes both cool and warm season crops. When summers get hotter as we move to the south the tactics change. You should now try to spare your cool-season vegetables the hottest summer weather. Cool-season vegetables that mature in a relatively short time are grown in either the spring or the autumn. The spring crop will benefit from being started indoors or in cold frames to give an earlier harvest and better quality. Choose early and fast maturing varieties. The autumn crop is sown directly in situ in the summer. Seedbeds and seedlings may have to be partly shaded to keep temperatures down. Cool-season vegetables that take a long time from sowing to harvest are sown to mature in the autumn. This means that they will be on the soil during the hottest part of the season, but unfortunately there isn't much choice here. If winters are mild (only short episodes of frost and snow) the slow maturing cool-season vegetables may be sown in the autumn in time for seedlings to emerge before the winter. The plants overwinter on the soil to get a really early start next spring. This method may also work in areas where there is deep snow cover. The snow protects the seedlings from extreme winter temperatures.
Potato tubers can be sprouted in a light but not to warm place four weeks before planting out to give an earlier crop. Just spread the tubers on a tray Garlic corms grow better if they have been exposed to cold temperatures and should be planted in the autumn or be kept in the coldest corner of the fridge for at least six weeks.
Seeds last for yearsQuite often you will not sow all the seeds in a bag. Do not throw the remainder away. Most seeds will last from one year to the next if they are stored in a dry and not to warm place. The germinativeness will be slightly reduced. For most plants this is a minor problem. Sow a few seeds extra and replant what emerges to get the plants where you want them. The umbellifer seeds (carrots, parsnip, salsify, scorzonera etc.) are among those with the shortest life expectancy. These plants are also the hardest transplant, and I recommend that you get new seeds every year. Most other seeds can be kept for at least two to three years. Cucurbit seeds (cucumber, squash, pumpkin etc.) are among the toughest and may germinate well after ten years at the bottom of your sock drawer (provided that the socks were clean).Top Thinning outThinning out is emotionally difficult. You normally feel that if you leave some extra plants the harvest will be bigger and there is always the concern that some plants may die. In this case it would be good to have some extra to throw in. This is just one of the ways in which gardeners fool themselves. Plants need a certain amount of space to grow well, and most plants can only be moved successfully when they are quite small. If some plants should die their neighbours will take advantage of this by growing both under and above ground in the direction of the empty space. These plants will benefit from the extra space and the total loss will seldom be great.Thinning out should be done when the plants are still small - between five and ten centimetres tall. It's important to do as little damage as possible to the remaining plants. If seedlings are closely spaced I usually put two fingers on the soil to keep it stable as I pull the excess seedlings out. Roots will be damaged anyway and if the soil is not already quite moist the plants benefit from watering. Top TransplantingMost plants can be transplanted when they are small to fill out gaps in the rows. All plants sown indoors also have to be transplanted. Vegetables are transplanted when they are growing vigorously as opposed to most other plants, which are usually transplanted, when they are dormant. This makes the operation more difficult.The roots of young and growing plants are delicate and fragile. The bigger the lump of soil that can be transferred undisturbed the better. Unless plants have been grown in pots they are still likely to lose most of their roots when transplanted. If you are not going to plant right away don't let the plants lie on top of the soil and dry out. Cover the roots immediately with moist soil to keep them alive. Water the plants well after transplanting and watch them closely for the next few days. If they show any signs of wilting remove some of the older leaves to balance the ratio of leaves to roots. If the weather is very sunny this may not be enough. Try to provide shade during the hottest hours of the day. A board suspended on bricks is one way to achieve this goal. It's better to transplant when a few days of cloudy weather can be expected. Give some extra water, but avoid excesses. The roots will need air too. Most plants should not be buried any deeper than they were before, but tomatoes and brassicas respond well if they are planted deeper. Some plants e.g. cabbage, broccoli and kale may actually benefit from being lifted and replanted. Plants with tap root e.g. carrots are the most difficult to transplant, but if there are big gaps in the rows it could still be worth a try. Small or malformed carrots are better than no carrots. Top
vegetables@frideen.com Last major update 2004-12-10 Copyright© Anders Frideen |
The carrots did reasonably well, and the scorzonera was the best I ever got. Spured by the success I sowed carrot and scorzonera together right from the start in 2003.
