In PART 1 we made some simple square blocks and then combined squares into representations of common garden box sizes for square foot gardening.

In PART 2 we added some pretty colours, some functionality and learned some excel math.

An essential part of gardening is to know when to plant and the length of your growing season. These are determined by Last Frost Date (last spring frost) and First Frost Date (first killing frost of fall). The frost dates are highly localized and are not limited by plant hardiness zones. Elevation, proximity to cities/ large bodies of water, snow cover all have an effect on the frost dates.

To download a finished garden planner complete with video tutorial go to this page – Updated 2014

Frost Dates

To determine your local frost date you can simply Google “frost dates

Links to frost dates:
Vesseys Seeds: http://www.veseys.com/ca/en/learn/reference/frost/canada
Canada Farmers Almanac: http://www.almanac.com/content/frost-chart-canada
USA Farmers Almanac: http://www.almanac.com/content/frost-chart-united-states

Adding your nearest home city to frost dates google search may narrow down it for you.

For my fost dates I use a last frost date of June 1 and a first frost of September 7 for a whopping 98 day growing season. This short growing season reduces what I can plant and increases the risks (has been known to snow in early July but i haven’t seen it).

Adding frost dates to your garden plan

Once you have these dates find a spot below your legend for your garden you did in the previous step. Merge some cells if you need to, but make Last Frost Date, First Frost Date and Growing Season headers.

format-cell-date-excel

The frost dates need to be in a date format. Select the two cells which will hold the dates, right click >> Format cells. Under Number tab, select date and then a date format which appeals to you. You can aldo change alignments and such while you are here. Click OK.
Now enter the dates into the boxes.

Excel can use dates in simple math functions, so to determine your growing season simply highlight the growing season cell, in the Function bar type:

=CELL ID of last frost date – CELL ID of first frost date ex. =F28-F27

These dates will be reffered to by other excel functions so don’t move them once they are done and correct.

Now we need to make a planting/growing schedule.

Make a growing schedule

For the planting schedule we need the following headers:

Plant Name:   Same plants as listed in your legend (can be cut/pasted for simplicity.

Transplant:    Yes or not – just indicates if this will be a transplant

Planting (weeks):  This is the planting weeks before/after the first frost date. Usually found on the seed packets or a few google searches should tell you. This is usually in weeks so I have formatted the math for working with weeks. Negative values indicate weeks before first frost which usually means transplants. Fill out this column for all desired plants.

Plant By: This is a calculated field  wich will simply add the planting weeks to the first frost dates. This column needs the cell properties changed to date.

Use the following formula:

= CELL ID of last frost date + CELL ID planting (weeks) ex: =$F$27+P42*7

The multiplication *7 at the end is to convert weeks to days, if you used just days in planting weeks – you don’t need the *7. Excel date math only works in days.

the $ signs in the first frost date CELL ID will make it a constant.

Now simply drag the complete cell down to fill in the entire column – should have a nice column showing when you should plant.

Germination (Days): This is also located on seed packets or found with a little difficulty online. Not overly necessary however I use it to determin an outside range for crop finish dates. This is filled out by hand.

Days after frost plant:  Some plants require a “buffer” after the frost date for planting, usually related to soil temperature, sunlight, etc. Negative numbers indicate planting before the last frost date, usually transplants however some seeds (Peas) can be direct planted before the last frost date. This is filled out by hand.

Transplant on/by:  This should only be filled out for transplant plants (copy/pasted into appropriate rows).

For transplant only plants utilize the following formula:

=CELL ID last frost date + CELL ID days after frost plant ex. =$F$27+Y42

Again, the $ for the last frost date  to make it constant.

Once you confirm the math works, copy/paste into additional transplant rows

Maturity (Days):  This is the days to maturity given on seed packets and needs to be filled out by hand. Days to maturity is only a guide as growing conditions determine when something is finished and ready to be harvested.

Done by: Or Harvest date, is calculated by adding the plant by, germination (days) and Maturity (days).  I dont really need the germination time added in however i like a buffer so I include it. These cells need the cell properties set to Date format.

Use the following formula:

=CELL ID Plant by + CELL ID Germination (days) + Maturity (days)
ex. =S42+V42+AE42

Once the math works, simply copy/paste or drag to fill in the rest of the column. This will give you an estimate on harvest times as the Maturity time can range depending on growing conditions (hence the germination buffer).

Crop 2?: Ive included this as some growing seasons are long enough to allow for a couple of crops of specific plants (peas, beans, radish, lettuce, etc.)

This is simply calculated by adding germination (days) and maturity (days) to the dont by date. This cell requires a date format as well. You could add a third/fourth crop as well in tropical areas.

= CELL ID done by + CELL ID Germination (days) + Maturity (days)
ex. =AH42+AE42+Y42

<plant-schedule-excel

 

Thats all for this series. Will be adding articles for trellising, extending growing seasons, plant varieties and such as I have time.

I have compiled an excel worksheet I have used to do all the things in this article series.
You can download it here as a zip file.


I utilize a modified for me version of Square foot Gardening. This method allows for very high yields in a very small areas. There are very strong advantages to this method and it is a must for people with limited space and time. By my estimations I can supply a family of five with fresh vegetables, preserves and frozen vegetables for nearly an entire year on less than 1000 square feet (excluding grains).

The primary advantages of this method are:

  • Easy weeding (vegetables actually shade out weeds)
  • No rototiller (once the soil is productive a simple rake/hoe)
  • Customizable soil mixtures per bed
  • Greater productivity/yield per square foot
  • Alot less water (plants shade themselves to keep in moisture)
  • Beds warm quicker so you can plant earlier and extend your season
  • Minimal thinning (plant fewer seeds)
  • Easy pest control and mitigation
  • Can quickly and easily change soils/plants

If you are interested in this gardening method, the below linked books provide all the basics, rules and information.

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