Many vegetables and flowers thrive when multiple seeds are planted per hole, cell or pot. Once germinated, thin out seedlings until only one strong plant remains per “spot.”
Planting too few seeds could leave space under your lights unused as well as extra seed starting mix lying around. To prevent this, it’s essential that you determine how many seeds should be planted at once.
Germination Rates
Have you ever planted seeds before, whether in a tray, container, or directly into the ground? Not every seed sprouts; many factors influence germination rates; once you understand these, you’ll be better able to decide how many to sow in any given location or container.
On its packaging, seeds often list their germination rate; this percentage – usually out of 100 – refers to how many seeds will germinate when all growing conditions have been met.
To determine the germination rate of seeds, a sample is planted and monitored over time for signs of germination. As each seed germinates, its Germination Percentage (GP) can be calculated and used to predict how many seeds will sprout at planting time.
Higher germination rates increase your odds that all the seeds will germinate, giving your garden plenty of plants. On the other hand, failure of even one seed to germinate could render an entire batch useless and lead to wasted money and effort.
Size also plays an important part in seed germination rates. Smaller seeds tend to sprout quicker, though even those that appear promising can fail if planted too deep or have other issues. It is always wise to plant multiple of each kind of seed type before thinninf them out after germination has taken place.
Seeds that have been stored too long often fail to germinate, so proper storage is vital. A cool and dry place like a glass jar should keep them alive until you’re ready to plant them. If in doubt as to how long your seeds have been sitting around, put a few in wet paper towel for 24 hours and see what happens; if nothing appears then they likely aren’t worth planting.
Seed Size
Seed size is an integral factor in the ability of seeds to germinate, grow and form strong seedlings, as well as their distribution, abundance and dispersal rates. Seed size has evolved through time due to multiple selection pressures; thanks to advances in phylogenetic methodologies and broad comparative data sets we are now able to trace its development across major plant groups.
Large seeds usually require less potting mix to germinate and flourish into plants than their smaller counterparts, prompting many gardeners to use a “quarter-inch” planting depth even though many crops require two or three times deeper planting depth than the width of their seeds. Plants planted too deeply lose energy trying to reach sunlight through layers of soil; eventually either they won’t sprout at all or succumb altogether.
Typically, one seed should suffice per hole, cell, or pot for crops such as squash, tomatoes, peppers, kale and broccoli – this allows you to save space under your grow lights as not all the seeds will sprout; with one exception being strawberries which should be planted individually.
No matter how many seeds you sow, always follow the specific instructions on your seed packet. Furthermore, it may be worthwhile checking out the back side for information such as how many to plant per square foot to conserve space and prevent overcrowding, which can hinder airflow and lead to fungal issues in a Tower Garden.
If using a microscope to assess seed size measurements, there are a few ways that can be utilized: box measurement which involves simultaneously and perpendicularly measuring length and width simultaneously and perpendicularly, as well as line measurements which measure distances between two points on a seed (best used with seeds that have simple shapes); line measurements which involve measuring distance between two points on an irregularly-shaped seed). Calibration should always be ensured before carrying out either method for accurate results.
Soil Conditions
Seeds only flourish and take root when their environment is suitable. Soil characteristics like texture and nutrient content determine its suitability for plant life; some are naturally better structured than others, but through effective management practices can improve conditions to facilitate healthy plant development.
Soil texture is determined by a combination of clay, sand and silt particles as well as organic matter content, with these components combined dictating its texture and the ease with which water and air move through it. Soils with poor drainage such as sandy, rocky or sand-like qualities often have poor drainage as water cannot readily infiltrate into them and instead pools on top causing root oxygen deprivation leading to plant death or even wilting and death of roots.
Soils that are too clayey are hard and compacted with very limited pore space. Heavy traffic in garden beds and vegetable gardens causes compaction that reduces pore sizes, making water harder to penetrate and bulk density rise, decreasing air exchange in the soil. This in turn decreases aeration.
Loamy soils make the ideal gardening soil, boasting a blend of sand, silt and clay particles for optimal structure, moisture retention and ease of cultivation. Loamy soils should be replenished regularly with organic matter to retain nutrients in them and maintain an ideal structure.
An effective rule of thumb when planting seeds is to set them at twice their width, as per instructions or experiment. When in doubt, it’s better to plant shallower so as to decrease any risk of being buried by too much dirt. This way, they’ll have enough light for proper germination.
As some seeds such as squash, tomatoes and peppers require the sunlight for growth to sprout, too much potting mix could prevent their ability to do so.
Light
Many seeds require light to break through their protective seed coats and germinate, meaning if these seeds were covered in soil they couldn’t access any sunlight needed for their development. Therefore it’s crucial that before beginning planting any particular type of seed it is important to understand its expected germination rate which should be included on its seed packet or online source (ie: Amazon). This information can usually be found there or can also be easily found online.
When gathering this information, remember that it reflects an average germination rate for that species and will differ depending on which plant species is in question. A typical seed packet might indicate that begonias and geraniums have an average germination rate of 70% – although this serves as a good starting point, you should also factor in other variables, including number of seeds planted and expected timeframe for their development before they can be planted out into your garden.
As part of your research process, pay special attention to the instructions included with each seed packet. This will provide an estimate of the optimum planting depth for each type of seed – this is vital because some may need to be planted deeper so they can break through the soil surface, while other are meant only to be minimally covered by dirt.
As a general guideline, when planting seeds you should do so to the depth that is three times their thickness. So for fat bean seeds this means planting one to three inches deep while thin carrot seeds only require light coverage. Most seed packages provide guidance as to what their optimal planting depths are for each variety.
Once your seedlings have germinated, it’s essential that they get enough light so they can reach their full potential before transplanting them to the garden. This is especially true when indoor gardening vegetables and herbs. Most seedlings require 12-16 hours of intense illumination a day to prevent becoming weak and leggy; you can achieve this using high-intensity grow lights or simply placing them near sunny windows regularly rotating them so they don’t become leggy or too lean.
