Module 5: Small garden, big harvest!

This module’s topic is gardening in small spaces. We’ll cover choosing the most appropriate varieties, containers, and  growing media, as well as proper watering and fertilizing. We’ll also learn specific techniques for intensive planting, container, squarefoot, strawbale, and vertical gardening.

At the end of this lesson, you’ll be able to

  • List characteristics for choosing varieties
  • Describe qualities needed for a container growing media
  • Describe requirements of a container for vegetable plantings
  • Describe proper watering techniques for containers
  • Describe fertilizer requirements for container plants and how it differs from traditional in ground gardening

Intensive planting

  • Intensive spacing or planting is growing crops as closely together as possible to maximize use of space. 
  • With intensive spacing, plants also act as “living mulches” that reduce weed pressure and water evaporation.  
  • Keep in mind, however, that overly close spacing and limiting pruning can result in reduced airflow and plant disease.


Plant fast and slow growing crops in the same row at the same time

Succession & Sequential planting

  • Successive gardening is for crops that have a very quick period from seed to harvest. Radishes (21-35 days), lettuce (30+ days), bush beans (50-60 days). 
  • Sequential gardening is when you replace an early season crop with a late season crop. Example:  replacing peas (cool/spring) with kale.

Choosing cultivars

  • Get the biggest return on your investment. Grow high yielding vegetables: tomatoes, lettuce, summer squash and edible pod peas. Not corn, broccoli, cauliflower.
  • Smaller varieties will go by descriptive language like “compact” or “bush” for vining crops (cucumbers, beans, squash, zucchini, watermelon, and pumpkins)
    •  Tomatoes use the terms determinate and indeterminate. Determinate tomatoes are “bush” varieties and do better in small spaces. Determinate plants produce flowers all at once. Indeterminate plants will produce flowers until frost.
    • Look for dwarf varieties. Example- Red Robin Tomato. Dwarf tomato that yields mid-large cherry tomatoes that can be grown in a six inch pot. Note: flavor may be impacted.
  • Choose disease resistant varieties, especially when limited with space.
    • Note: you need to have a positive ID on diseases to properly choose disease resistant varieties


  • Right size container for the plant. In really small spaces, like window boxes, you can plant herbs and edible flowers. Many herbs can be grown in six inch pots. 
  • For larger plants, rely on buckets, bags, or large pots. 
  • One benefit of container gardening is you can choose where to put the pot. 
  • Be aware, with large pots, once it is filled with your potting medium, it may become very heavy. Carefully choose their final home.
  • 1-5 gallon capacity for most crops
  • Small pots will dry out more quickly!

  • Repurpose household materials. There are unlimited options available for containers. Cheap plastic pots will deteriorate, but will get the job done.
  • Wood containers are susceptible to rot, but redwood and cedar are relatively resistant. Avoid painted wood, treated wood with creosote or other toxic compounds
  • Things to avoid: No clear containers; you’ll burn the roots. Avoid tires

  • Allows excess water to drain from the pot.
  • Allows pots to dry out between waterings, providing air to the pores in the growing media that roots require from time to time.
  • Prevents the buildup of excess minerals by leaching  minerals through the growing media.
  • Encourages deep watering, so all the roots are saturated.

  • Don’t use garden soil because in containers it will compact too quickly. Soilless mixes and some pasteurized soil mixes contain additives like perlite, vermiculite, and peat. These additives help the potting media drain better, retain nutrients, and retain moisture.
  • Make your own: equal parts sand or perlite, loamy garden soil, and peat moss or coconut coir. May be cheaper to make your own, depending on your situation.
  • Rooftop or Balcony? Lightweight soilless potting mix.

  • Most likely hand watering
  • Water more often.  When you plant in containers, keep in mind you will need to water daily, and sometimes twice a day. Soil mixes in containers will not retain moisture as well as the soil in the ground. The soil in a container will also be warmer than in the ground, causing the soil moisture to evaporate more quickly than in the ground.
  •  Is your watering source handy?Its important to think about where your water source is- is it convenient? . 
  • Elevate the container off the ground with 2×4 or bricks or whatever
  • Water the roots, not the foliage! Try to avoid getting the foliage wet- you want to water the soil, not the leaves. Excess moisture on plant leaves will encourage fungal diseases.
  • When plants grow in the ground, the roots bring up nutrients from subsoil. Microbes  make nutrients available from the subsoil. This isn’t happening in containers. Soil in containers needs added nutrients!

Primary plant nutrients

  • To complete their life cycle, plants need 17 nutrients in different amounts. A plant gets their carbon, hydrogen, and oxygen from air and water. This accounts for 94% of the plant’s weight. The other 6% of the plant’s weight comes from soil nutrients. 
  • Of the remaining 14 nutrients, nitrogen, phosphorus, and potassium are the primary macronutrients.
  • Because containers are watered so often, the nutrients do not stay in the potting mix for long.
Nitrogen (n)Rapid foliage growth; green color
PhosphorusPromotes root formation and growth; affects quality of flower, fruit, and seed production. 
PotassiumHelps plants overcome drought stress; improves winter hardiness

Fertilizer basics

copy from previous module

Square Foot Gardening

  • Traditional row planting wastes space. With square foot gardening, you can produce 5 times the yield in the same amount of space.
  • Divide into 1 foot square sections. Use string or wood slats to mark the squares. Your markers can be removable or permanent. 
  • For vining vegetables, you can add a trellis on the north end. Lattice will work nicely. Organize planting based on height and be sure to plant the tallest plants on the north side so they don’t shade out the shorter crops.
  • Considering using treated wood to build a raised bed? Do not use copper-arsenate treated wood. It’s unclear if it will leach into soil or plants, but will come into contact with your skin.  Pressure treated will work better. 
  • Build your beds 4 foot wide. The length is up to you.Use boards 6-10 inch wide. 
  • Benefits of raised beds:
    • No need to till. 
    • They are taller and more accessible. You can make beds at waist high for those with mobility issues.
  • Challenges
    • It is difficult to grow bigger crops. The crops can over power the rest of the crops in the garden. But you can address this in your cultivar choices. 
  • Fill: Don’t use straight garden soil. Use compost, peat, and vermiculite. 
  • Add extra fertilizer, since compost won’t have an analysis on it. 

Extra LargeLargeMediumSmall
1 plant 12” apart4 plants6” apart9 Plants 4” apart16 plants3 inches apart
BroccoliCabbagePepperLeaf LettuceSwiss ChardMarigoldsBush beansSpinachBeetsCarrotsRadishesOnions
  • Note: foliar diseases are much more likely to occur- choose disease resistant varieties. Still need good air circulation and may need to prune some crops (tomatoes).
  • If you want to rotate your crops, you’ll need multiple beds.
  • Use mulch: straw, hay, newspaper- barrier. Snip bottom leaves of tomatoes to protect against diseases. 
  • Be sure the raised bed gets 2 inches of water per week. Raised beds use more water because the soil is warmer.

Straw bale gardening

  • A variety of crops can grow in straw bales,including tomatoes, peppers, eggplant, squash, melons, and herbs. 

List a benefit of straw bale gardening in the chat.

  • No need to dig in the soil
  • Good for poor, compacted soil, or your soil is contaminated by disease or other contaminants like lead
  • If you don’t have garden space in full sun, you can place on asphalt
  • Up off ground, so helpful for those with limited mobility
  • No container or potting mix to buy 
  • Can be used at the end of the season to enrich the soil.

Curing the bale

  • Start with a bale of wheat or oat straw. 
  • Age of bale doesn’t matter as long as the baling twine is still tight. Hay bales can be used, but they contain more weed and grass seeds that will grow.
  • Site the bale in a location with at least 6 hours of sun, just like a regular garden.
  • Make sure the twine is on the sides
  • The conditioning process starts with watering the bale thoroughly for a few days. Next you’ll add a high nitrogen fertilizer like urea (46-0-0) for several days. The bale will begin to warm up, then slowly cool down. After three-four weeks, your bale should be ready. 
  • You can find directions on how to cure your bale here.  

Planting the bale

  • Once cool to touch, you can plant your bale garden. If you are unsure, you can use a meat thermometer to measure the heat several inches down inside the bale.
  • Use seed package or plant tag for spacing requirements. If it says to plant 18 inches apart, then that is the same for the bale. 
  • Take a sharp trowel and separate the straw. 
  • Place the plant down to the first leaf and let the straw fill in around it. 
  • You’ll want to be careful not to cut the twine while planting. 
  • If you want to plant seeds, like beans, place a small layer of compost mixed with soil on the top of the bale, like icing on a cake, and plant the seeds directly into the soil. Cover the seeds with a light dusting of soil or peat moss and water well. 
  • When planting tomatoes, you will want to stake them with a 6-foot stake because cages do not work well to support the plant.

  • Watering: Keep the bales moist by watering them daily and don’t let the bales dry out. If the bales aren’t kept moist by sprinklers, a porous soaker hose or drip system can be used to apply water. 
  • Expect weeds. Get them while they are small. 
  • Expect mushrooms. Don’t eat.
  • The straw does not provide all the essential nutrients needed for plant growth like soil or a premium potting mix does, so straw bale plants need to be fertilized once a week using a water soluble garden fertilizer containing nitrogen, phosphorus, and potassium and micronutrients.
  • The oldest leaves of vegetable plants turn yellowish if they are deficient in nitrogen. Nitrogen deficiency is common when growing plants in straw bales. Potassium deficiency shows up as a purpling of the leaves and brown leaf edges can indicate a potassium deficiency. 
  • Bales will usually last for only one growing season, two at the very most. 
  • After the growing season is over and the crops have been harvested, the bales can be recycled by placing them in the compost pile or working the rotted straw into the soil.

Vertical gardening

  • Use fence, wall, or other structure, or create a structure using trellises, netting, strings, cages, or poles to support the plants as they grow upwards. 
  • Cucumbers, tomatoes, melons and pole beans work well with trellis. With larger crops, melons (depending on the type), squashes, and pumpkins will need supports like hammocks. 
  • Some crops will have tendrils (peas) and some you’ll need to train or tied to the structure (tomatoes).
  • Install supports at planting- don’t wait until the plant needs the structure. Tendency to break the plants when that happens. If you have ever tried to cage a tomato once its grown, for example.
  • Be aware of shadows from vertical plantings.

  • Strawberry planters are an example of vertical gardening. 
  • Pallet planting is another example of vertical gardening. 
  • Can get creative! Look for ideas on pinterest!


Common Crops for Community Gardens

Raised Beds and Containers for Community Gardens

Mulches for Home Gardens and Plantings

Container Gardening

Trellising, Staking, and Caging—Vertical gardening techniques for vine-type vegetables

Straw Bale Gardening

Straw Bale Gardening

Vegetable Gardening in Containers

Square Foot Gardening

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